Photovoltaic panel-interfaced solar-greenhouse distillation systems

ABSTRACT

A hybrid photovoltaic panel-interfaced distillation with and without a hydrophobic microporous membrane distillation process is provided that is capable of utilizing solar waste heat to perform liquid distillation while co-generating solar electricity. Solar waste heat co-generated at a photovoltaic panel is effectively utilized by in situ distillation liquid as an immediate heat sink in thermo contact with the photovoltaic panel, thus providing beneficial cooling of the photovoltaic panel and co-making of distillation products while generating electricity with significant improvement on total-process solar energy utilization efficiency. Its enabled beneficial utilization of waste heat can provide a series of distillation-related products such as: freshwater, sea salts, distilled water, distilled ethanol, hot water, hot steam, saline/brine products, and brine photobiological cultures for production of advanced biofuels and bioproducts, in addition to solar electricity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 13/569,261 filed on Aug. 8, 2012 that is acontinuation-in-part of U.S. patent application Ser. No. 12/975,307filed on Dec. 21, 2010, which issued as U.S. Pat. No. 8,673,119 on Mar.18, 2014 and is a continuation-in-part of U.S. patent application Ser.No. 12/918,811 filed on Aug. 21, 2010, which issued as U.S. Pat. No.8,753,837 on Jun. 17, 2014 and is the National Stage of InternationalApplication No. PCT/US2009/034780 filed on Feb. 20, 2009, which claimsthe benefit of U.S. Provisional Application No. 61/066,770 filed on Feb.22, 2008, U.S. Provisional Application No. 61/066,771 filed on Feb. 22,2008, and U.S. Provisional Application No. 61/066,832 filed on Feb. 23,2008. The entire disclosures of all of these applications and patentsare incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to solar energy technology. Morespecifically, the present invention provides a hybrid solarpanel-interfaced distillation with and without a hydrophobic microporousmembrane distillation process for co-generating electricity whileutilizing its waste solar heat to make a series of distillation relatedproducts such as distilled water, distilled ethanol, sea salt,saline/brine products, and advanced biofuels and bioproducts.

BACKGROUND OF THE INVENTION

Photovoltaics is the field of technology and research related to thepractical application of photovoltaic cells in producing electricityfrom solar radiation (sunlight). Photovoltaic cells are oftenelectrically connected and encapsulated as a module (photovoltaicpanel). Photovoltaic electricity generation employs solar photovoltaicpanels typically containing a number of photovoltaic cells containing aphotovoltaic material. Materials presently used for photovoltaicsinclude monocrystalline silicon, polycrystalline silicon, amorphoussilicon, cadmium telluride, and copper indium selenide/sulfide. When aphoton is absorbed by a photovoltaic cell, it can produce anelectron-hole pair. One of the electric charge carriers may reach thep-n junction and contribute to the current produced by the solar cell,or the carriers recombine with no net contribution to electric current,but generating heat. Furthermore, a photon with its energy (hν) belowthe band gap of the absorber material cannot generate a hole-electronpair, and so its energy is not converted to useful output and onlygenerates heat if absorbed. For a photon with its energy (hν) above theband gap energy, only a fraction of the energy above the band gap can beconverted to useful output. When a photon of greater energy is absorbed,the excess energy above the band gap is converted to kinetic energy ofthe carrier combination. The excess kinetic energy is converted to heatthrough phonon interactions as the kinetic energy of the carriersslowing to equilibrium velocity. Consequently, photovoltaic cellsoperate as quantum energy conversion devices with thermodynamicefficiency limit. Today's photovoltaic panels typically convert about15% of the solar energy they capture from the sun into electricity,leaving 85% to be dissipated as heat. This creates a major thermaldesign challenge since every degree of temperature rise in thephotovoltaic panels reduces the power produced by 0.5%. For example, ahigh quality monocrystalline silicon solar cell, at 25° C. celltemperature, may produce 0.60 volts open-circuit. The cell temperaturein full sunlight, even with 25° C. air temperature, will probably beclose to 45° C., reducing the open-circuit voltage to 0.55 volts percell.

Therefore, a major design challenge for the manufacturers ofphotovoltaic panels is keeping them cool. Adding forced air coolingwould add to the cost and maintenance requirements and consume asignificant amount of energy; therefore, nearly all photovoltaic panelsare cooled solely by natural convection. This explains why, presently,most commercial modules are constructed in such a way that air can flowunder the photovoltaic panels in order to maximize convective cooling.However, in all those cases, the solar heat is wasted without anyutilization. Therefore, any new approach that could utilize and removethe solar waste heat in a productive manner while generatingphotovoltaic electricity would be helpful to improving the overallsystem productivity and energy efficiency.

Desalination of seawater is another major challenge related to energyand environmental sustainability on Earth. In many parts of the world,freshwater is in short supply. Salt is often quite expensive to removefrom seawater, and salt content is an important factor in water use,i.e., potability. Currently, multi-stage flash distillation and reverseosmosis are the two major engineering processes for desalination ofseawater. Both of the processes are energy intensive and dischargesignificant amounts of brine liquid into the environment, which is anenvironmental concern.

International Application No. PCT/US2009/034780 discloses a set ofmethods (1) on synthetic biology to create designer photosyntheticorganisms (such as oxyphotobacteria, also known as blue-green algae) forphotobiological production of advanced biofuels such as ethanol fromcarbon dioxide (CO₂) and water (H₂O) and (2) on a greenhousedistillation system technology to harvest the photobiologically producedethanol from the ethanol-producing algal liquid mass culture.

SUMMARY OF THE INVENTION

The present invention is directed to a method based on a hybridphotovoltaic panel-interfaced distillation technology with and withoutthe use of a hydrophobic microporous membrane distillation process, inwhich the cooling of solar photovoltaic panel is achieved by an in situliquid-containing distillation chamber so that the solar waste heat isbeneficially utilized, i.e., removed, through liquid distillation,providing effective cooling of the photovoltaic panel for enhanced solarenergy utilization efficiency. This technology is capable of performingsolar-greenhouse distillation for various liquids to harvest certainsolvents, e.g., distilled water, ethanol, and solute, e.g., salt andsugar, while co-generating solar electricity. The photovoltaicpanel-interfaced distillation system technology can also serve as aspecial tool for desalination of seawater to make freshwater (distilledwater), sea salt, boiled water, hot steam and saline/brine productswhile co-generating photovoltaic electricity. Since the presentinvention enables beneficial utilization of photovoltaic panel wasteheat for a liquid-evaporation-vapor-condensation distillation process,it not only addresses the waste heat issue in photovoltaics but alsoprovides other benefits including helping overcome the challenges inseawater desalination and in algal mass culture for production ofdistilled water, sea salt, advanced biofuels and bioproducts importantto sustainable development on Earth. Exemplary embodiments in accordancewith the present invention include the photovoltaic panel-interfaceddistillation solarhouse apparatuses, the associated operationalprocesses and applications thereof.

According to one of exemplary embodiments, the photovoltaicpanel-interfaced distillation system comprise: an air-erectable basechamber with the insulator support plate as its top and part ofsolarhouse walls below the level of photovoltaic solar panel as itswalls containing the chamber air space and condensate liquid storagespace; an air-erectable distillation chamber with the heat-conductingtransparent plate film above the photovoltaic solar panel as bottom andpart of solarhouse walls above the level of the photovoltaic solar panelas its walls containing the distillation chamber liquid and headspace; aheat-insulating side layer around the solarhouse to minimize loss ofheat to the environment including the surrounding seawater; at least onepair of source liquid inlet and outlet connected to distillation chamberat the points below the seawater level; a set of condensate collectingducts located around the solarhouse inner walls below the level of theceiling and preferably just below the point of intersection of the wallsand ceiling for collecting condensate droplet that forms as distillationliquid vapor condensing at the ceiling and then runs down the ceilingtoward the walls; an inter-chamber condensate-transporting tube thatcollects and transfers the condensate from condensate collecting duct ofthe distillation chamber above the photovoltaic solar panel into thebase chamber condensate liquid storage space; a set of electricityoutput terminals of the solar photovoltaic panel for harvesting thesolar electricity generated; and a condensate liquid outlet withvalve/tube connected at the bottom of the base chamber for harvestingthe product water.

In accordance with one exemplary embodiment, a photovoltaicpanel-interfaced distillation solarhouse system comprises a photovoltaicsolarhouse coupled with a distillation chamber through a self-sustainedcirculating coolant fluid for heat exchange to make freshwater bydistillation while co-generating solar electricity.

According to one of various embodiments, the photovoltaicpanel-interfaced distillation system comprise: a solar photovoltaicpanel with electricity output terminals and with a heat-conductingplate/film as its back surface; a liquid feed chamber withheat-conducting plate/film as its top and a hydrophobic microporousplate/membrane as its bottom; at least one pair of energy-saving liquidfeed/discharge tubes connected to the two opposite sides of the liquidfeed chamber; a base condensation chamber that contains air space andcondensate liquid space; a hydrophobic microporous plate which serves asthe bottom of the liquid feed chamber and which also serves as the topof the base condensation chamber; solarhouse walls that join withheat-conducting plate/film and hydrophobic microporous plate forming theliquid feed chamber and the base condensation chamber; and a condensateoutlet connected to the bottom of the base condensation chamber forharvesting product liquid.

In accordance with the present invention, the solar waste heat generatedat a photovoltaic panel is effectively utilized, i.e., removed, by insitu distillation as a liquid evaporation and re-condensation processwith its distillation liquid as an immediate heat sink in thermalcontact through a heat-conducting transparent protective plate or filmwith the photovoltaic panel, providing effective cooling of thephotovoltaic panel for enhanced solar energy utilization efficiency.Exemplary embodiments of the present invention enable the utilization ofthe associated solar waste heat to drive liquid distillation to make aseries of beneficial products including, but not limited to, freshwater,distilled water, distilled ethanol, hot steam, sea salts, saline/brineproducts and saline/brine photobiological cultures, in addition to solarelectricity. Therefore, use of the present invention withgreenhouse-distillation-related applications yields significantly highersolar energy utilization efficiency than the conventional use of aphotovoltaic panel for solar electricity generation alone.

Exemplary embodiments in accordance with the present invention serve asan effective tool for desalination of seawater to make freshwater, seasalts and brine products while simultaneously co-generating solarelectricity. Since the photovoltaic panel-interfaced distillationprocess is operated in a sealed solarhouse chamber, the distillationliquid can be protected from contaminates from which a conventional openpond salt farm suffers including rain, dust, insects, animal waste suchas bird droppings and other undesirable environmental elements orcontaminates. Therefore, use of a rain-proof/dust-proof photovoltaicpanel-interfaced distillation solarhouse more reliably produces cleanand quality sea salt products than a conventional salt farm. Unlike theconventional open pond/pan salt farms that generally require arelatively dry season (any unseasonal rains could ruin their salt farmharvest), the use of a photovoltaic-panel-interfaced distillationsolarhouse system enables the making of quality sea salts fromseawater/brine even in a rainy season or rainy geographic area.

According to another exemplary embodiment of the present invention, thephotovoltaic panel-interfaced distillation with and without a membranedistillation process can be used both on water such as sea surfaceand/or on lands including roof tops for generating a number ofdistillation products of choice while co-generating solar electricity.Any number of various photovoltaic panel-interfaced distillation systemsare used in series, in parallel, and/or in combination with certainsunlight-concentrating mechanism such as sunlight focusing lens andmirror systems, and with photobioreactors/greenhouse distillationsystems to achieve more desirable results in desalination and harvestingof advanced biofuels and bioproducts such as ethanol while co-generatingsolar electricity. Therefore, the present invention represents aclean/green solar energy technology system that has many applicationsfor sustainable development on Earth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of an embodiment of a photovoltaicpanel-interfaced solarhouse distillation system in accordance with thepresent invention that enables the utilization of solar waste heat forliquid distillation while generating solar electricity;

FIG. 2A is a representation of an embodiment of an arch-shapedphotovoltaic panel-interfaced solarhouse distillation system inaccordance with the present invention as an example of seawaterdistillation for making freshwater and brine while generating solarelectricity;

FIG. 2B is a representation of an embodiment in using a layer ofwettable transparent material in a photovoltaic panel-interfacedsolarhouse distillation system for generating solar electricity anddistillation products at many places including leveled or non-leveledsloping fields, hill sides, roofs and walls facing sunlight;

FIG. 2C is a representation of an embodiment in using a base chamber airspace as a floatation buoyancy mechanism in an air-erectable andfloatable photovoltaic panel-interfaced solarhouse distillation systemfor co-generating solar electricity and distillation products on water,sea surface, and/or on lands and roof tops;

FIG. 2D presents a front view of an embodiment of an air-erectable andfloatable photovoltaic panel-interfaced solarhouse distillation systemwith heat-insulating side walls and source liquid inlet and outletimmersed in seawater for co-generating solar electricity anddistillation products;

FIG. 2E presents a front view of an embodiment of an air-erectable andfloatable photovoltaic panel-interfaced solarhouse distillation systemusing a base chamber air space and inner inter-spaces betweendistillation chamber wall and solarhouse outer wall for co-generatingsolar electricity and distillation products on water, sea surface,and/or on lands and roof tops;

FIG. 2F is a representation of an embodiment in using a basecondensation chamber air space as a floatation buoyancy mechanism in anair-erectable and floatable photovoltaic panel-interfaced hydrophobicmicroporous plate membrane distillation system for co-generating solarelectricity and distillation products;

FIG. 2G presents a front view of an embodiment of an air-erectable andfloatable photovoltaic panel-interfaced hydrophobic microporous platedistillation system using energy-saving liquid feed/discharge tubes forco-generating solar electricity and distillation products on a seawatersurface;

FIG. 3 is a representation of an embodiment of a photovoltaicpanel-interfaced solarhouse distillation system in accordance with thepresent invention equipped with a flexible dry air pump and a tail gascondensing/vent system as an example of seawater distillation for makingfreshwater and sea salt while co-generating solar electricity.

FIG. 4 is a representation of an embodiment of a multifunctionalphotovoltaic panel-interfaced solar-greenhouse distillation system inaccordance with the present invention using a cooling water-chamberceiling system, a flexible CO₂ feeding source, and a tail gascondensing/vent system for making saline/brine photobiological cultureand greenhouse distillation while generating solar electricity;

FIG. 5 is a representation of an embodiment of a tail gascondensing/vent unit (system) that comprises a cold-water-bath chambercooling a tail-gas condensing tube coil, a gas/vapor-condensate chamber,and a vertical venting tube;

FIG. 6 is a representation of the front view of an embodiment of asunlight-concentrating photovoltaic panel-interfaced solarhousedistillation system with a sunlight focusing lens/mirror system;

FIG. 7 is a representation of the front view of an embodiment of a lowertemperature (<100° C., typically 4-70° C.) photovoltaic panel-interfacedsolarhouse seawater distillation system (left) coupled with asunlight-concentrating higher-temperature (>100° C.) tolerantphotovoltaic panel-interfaced solarhouse distillation system (right) formaking freshwater, boiled water, hot steam and distilled water whilegenerating solar electricity;

FIG. 8A is a representation of an embodiment of a modified photovoltaicpanel-interfaced solarhouse system for making hot liquid such as hotwater while generating solar electricity;

FIG. 8B is a representation of an embodiment of a modified photovoltaicpanel-interfaced solarhouse system for making hot liquid whilegenerating solar electricity on leveled fields, slope hill sides, roofsand walls;

FIG. 8C is a representation of an embodiment of a modified photovoltaicpanel-interfaced solarhouse system with two liquid chambers for makinghot liquid while generating solar electricity on leveled fields, hillsides, roofs and walls;

FIG. 8D is a representation of an embodiment of a modified photovoltaicpanel-interfaced solarhouse system with a heat-insulating transparentplate or film retaining solar heat for making hot liquid whilegenerating solar electricity on hill sides, roofs and walls;

FIG. 8E is a representation of a photovoltaic solar-greenhousedistillation system coupled through a self-sustained circulating coolantfluid for heat exchange to make freshwater by distillation whileco-generating solar electricity;

FIG. 8F is a representation of a photovoltaic panel-interfacedhydrophobic microporous plate distillation system coupled through aself-sustained circulating coolant fluid for heat exchange to makefreshwater by distillation while co-generating solar electricity;

FIG. 8G is a representation of a photovoltaic panel-interfacedhydrophobic microporous plate distillation system with a mechanism tocontrol the two modes of hydrophobic microporous plate distillation:direct contact membrane distillation vs. air gap membrane distillationto make freshwater while co-generating solar electricity;

FIG. 9A is a representation of the front view of an embodiment of anintegrated system of photovoltaic panel-interfaced distillationsolarhouses (middle, and right) coupled with ethanol-producing brinephotobiological culture distillation greenhouse (left) for ethanolproduction and harvesting with multistage distillation while generatingsolar electricity; and

FIG. 9B is a representation of an embodiment of an integrated system ofphotovoltaic panel-interfaced distillation solarhouses (middle, andbottom) coupled with ethanol-producing brine photobiological culturedistillation greenhouse (top) for ethanol production and harvesting withmultistage distillation while generating solar electricity.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments in accordance with the present invention aredirected to a method based on a hybrid photovoltaic panel-interfaceddistillation technology system with and without the use of a hydrophobicmicroporous membrane distillation process for generation of electricity,freshwater, distilled water, hot steam, salts, saline/brine products,advanced biofuels and bioproducts such as ethanol. Methods in accordancewith the present invention yield significantly higher total solar energyutilization efficiency than that of a photovoltaic panel for electricitygeneration alone.

Presently, the majority of commercial photovoltaic panels (modules) areused typically with an inverter to convert the DC to AC electricity forgrid connected power generation. Based on the solar energy conversionefficiency of around 15% for the presently available commercialphotovoltaic panels, about 85% of the solar energy is dissipated as heatat the photovoltaic panels. As mentioned before, the waste solar heatenergy can often heat up the photovoltaic panels and result in anegative effect on photovoltaic cell energy conversion efficiencies. Thepower generated by photovoltaic panels decreases as their temperatureincreases at a rate of about 0.5% per degree Centigrade (° C.) at atemperature above 25° C. Therefore, a major design challenge for themanufacturers of photovoltaic panels is keeping them cool. Presently,most commercial modules are constructed in a way typically to allow airflow under the panels in order to maximize convective cooling. However,in all those cases, the solar heat is wasted without any utilization.Consequently, the conventional use of photovoltaic panels wastes as muchas about 85% of the solar energy. The present invention overcomes thischallenge through productive utilization of the associated solar wasteheat with a liquid-evaporation-vapor-condensation-based distillationprocess, resulting in a major improvement on solar energy utilizationefficiency and providing a series of win-win benefits from electricitygeneration to making of distilled water, distilled ethanol, sea salt,hot steam, brine, advanced biofuels and bioproducts.

The hybrid photovoltaic panel-interfaced solarhouse distillation methodutilizes or removes the solar waste heat generated at a photovoltaicpanel by in situ solarhouse distillation with its distillation liquid asan immediate heat sink in thermal contact through a heat-conductingtransparent protective plate or film with the photovoltaic panel,providing effective cooling of the photovoltaic panel for enhanced solarenergy utilization efficiency. Under certain conditions, the utilizationof the associated solar waste heat provides an effective cooling processto maintain a relatively stable temperature environment beneficial tothe performance of photovoltaic panels. Use of the photovoltaicpanel-interfaced distillation system enables the beneficial utilizationof the solar waste heat to drive liquid distillation to produce a seriesof beneficial products including, but not limited to, freshwater,distilled water, distilled ethanol, hot steam, sea salts, saline/brineproducts and saline/brine photobiological cultures, in addition to solarelectricity. Furthermore, use of the photovoltaic panel-interfaceddistillation technology and its associated brine product facilitates thedevelopment, screening, and use of certain high salinity-tolerantphotosynthetic organisms such as algae to enable utilization of brineliquid as a photobiological mass culture medium for production ofadvanced biofuels and bioproducts. As a result, use of this inventionwith photovoltaic-interfaced-distillation-related applications yieldssignificantly higher total solar energy utilization efficiency andprovides more benefits than the conventional use of a photovoltaic panelfor solar electricity generation alone.

Accordingly, the present invention provides, inter alia, methods forproducing solar electricity, freshwater, distilled water, distilledethanol, hot steam, sea salts, saline/brine products, andsalinity-tolerant photobiological cultures based on photovoltaicpanel-interfaced distillation technology systems with and without usinga hydrophobic microporous membrane distillation process. The variousaspects of the present invention are described in further detailhereinbelow.

Photovoltaic Panel-Interfaced Distillation Systems

Referring to FIG. 1, in one embodiment, a photovoltaic panel-interfaceddistillation solarhouse system 100 is illustrated. The photovoltaicpanel-interfaced distillation solarhouse system is a sealed distillationliquid chamber system that includes a bottom- or back-insulated solarphotovoltaic panel 101 mounted on an insulator base 102 constructed of asupport material. The photovoltaic panel is in communication with solarelectricity output terminals 112 for harvesting the electrical energygenerated. These terminals can be in communication with an electricalload or a storage source such as one or more batteries. Aheat-conducting transparent protective plate or film 103 is providedinterfacing in between the photovoltaic panel 101 front surface and thedistillation chamber liquid 104. The solarhouse system also includes atilted or angled vapor-condensing transparent ceiling 105 constructedfrom a transparent material such as transparent plastic cover andforming the top of the solarhouse system and a plurality of walls 106forming the sides of the solarhouse system and supporting thetransparent ceiling 105. Suitable materials for the walls 106 include,but are not limited to, liquid-tight and air-tight sealing materials,e.g., transparent plastic film. The distillation chamber is formed bythe heat-conducting transparent protective plate or film 103 (on top ofthe photovoltaic panel 101 front surface) as its bottom, the walls 106as its sides, and the transparent ceiling 105 of the solarhouse systemas its (the chamber's) top. The headspace 115 within the chamber abovethe distillation liquid 104 allows vapor 113 from the distillationliquid to travel up to the ceiling (inner surface) to be condensed thereforming condensate droplet 114.

A set of condensate-collecting ducts 107 are provided and are locatedaround the solarhouse walls below the level of the ceiling 105 andpreferably just below the point of intersection of the walls andceiling. The condensate-collecting ducts form a narrow channel or gutterfor collecting condensate 114 that forms from the condensation ofdistillation liquid vapor 113 at the ceiling and then runs down theceiling toward the walls. At least one condensate collecting tube 108 isprovided in communication with the condensate-collecting ducts 107 andone or more condensate tanks 109, linking the condensate collectingducts to the condensate tank. The solarhouse system also includes atleast one source liquid inlet 110 and at least one adjustable liquidoutlet 111 passing through the walls of the solarhouse system. The inletand outlet are in communication with the distillation liquid 104 withinthe solarhouse system. The adjustable liquid outlet 111 is spacedextending from the walls of the solarhouse system up to a height H4 thatis higher than the level of the distillation liquid 104. The liquidoutlet 111 extended from the distillation chamber is adjustable by theheight H4 above the photovoltaic panel.

According to another embodiment, a photovoltaic-panel-interfaceddistillation solarhouse can be in various forms or shapes including, butnot limited to, the form of photobiological growth chambers or growthbags that can be made from various synthetic materials such as certaintransparent plastic or polymer materials. As illustrated in FIG. 2A, forexample, a photovoltaic panel-interfaced distillation solarhouse system200 is provided as an arch-shaped distillation liquid chamber system.This solarhouse system includes a sealed distillation liquid chambersystem that includes a bottom- or back-insulated solar photovoltaicpanel 201 mounted on an insulator base 202 constructed of a supportmaterial. The photovoltaic panel is in communication with solarelectricity output terminals 212 for harvesting the electrical energygenerated. These terminals can be in communication with an electricalload or a storage source such as one or more batteries. Aheat-conducting transparent protective plate or film 203 is providedinterfacing in between the photovoltaic panel 201 front surface and thedistillation chamber liquid 204. The solarhouse system also includes anarch-shaped or curved vapor-condensing transparent ceiling 205constructed from a transparent material such as transparent plasticcover and forming the top of the solarhouse system and a plurality ofwalls 206 forming the sides of the solarhouse system and supporting thetransparent ceiling 205. Suitable materials for the walls 206 include,but are not limited to, liquid-tight and air-tight sealing materials,e.g., transparent plastic film. The distillation chamber is formed bythe heat-conducting transparent protective plate or film 203 (on top ofthe photovoltaic panel 201 front surface) as the chamber's bottom, thewalls 206 as the chamber's sides, and the arch-shaped or curvedvapor-condensing transparent ceiling 205 as the chamber's top. Theheadspace 215 within the distillation chamber above the distillationliquid 204 allows vapor 213 from the distillation liquid sea water totravel up to the ceiling (inner surface) to be condensed there formingcondensate droplet 214.

A set of condensate-collecting ducts 207 are provided and are locatedaround the solarhouse walls below the level of the ceiling 205 andpreferably just below the point of intersection of the walls andceiling. The condensate-collecting ducts form a narrow channel or gutterfor collecting condensate 214 that forms as distillation liquid vapor213 condensing at the ceiling and then runs down the ceiling toward thewalls. At least one condensate collecting tube 208 is provided incommunication with the condensate-collecting ducts 207 and one or morecondensate tanks 209, linking the condensate collecting ducts to thecondensate tank. A condensate tube outlet 216 is extended into thecondensate tank 209. The solarhouse system also includes at least onesource liquid inlet 210 and at least one adjustable liquid outlet 211passing through the walls of the solarhouse system. The inlet and outletare in communication with the distillation liquid 204 within thesolarhouse system. The adjustable liquid outlet 211 is spaced extendingfrom the walls of the solarhouse system up to a height H5 that is higherthan the level of the distillation liquid 204. The liquid outlet 111from the distillation chamber is adjustable by the height H5 above thephotovoltaic panel. As illustrated, the liquid inlet 210 is a sea wateror saline water inlet, and the collecting tank 209 is a freshwatercollecting tank that collects the condensate 214 as freshwaterultimately from the sea water.

Another exemplary embodiment of a modified photovoltaic-panel-interfacedsolarhouse 1200 is illustrated (FIG. 2B) that can be used for solardistillation while co-generating solar electricity at many placesincluding leveled fields and slope hill sides where solarhouses areinstalled preferably with a tilted angle to face sunlight. Thissolarhouse system 1200 uses a layer of hydrophilic transparent materialwettable with distillation liquid 1204 under the chamber headspace 1215in a sealed distillation liquid chamber system that includes a bottom-or back-insulated solar photovoltaic panel 1201 mounted on an insulatorbase 1202 constructed of a support material. The use of a layer ofhydrophilic transparent material wettable with distillation liquid 1204on solar panel 1201 surface ensures that the distillation liquid willfully cover the solar panel surface favorable for distillation even whenthe solarhouse is unleveled or tilted against the horizontal line withrespective to the gravity. According to one of the various embodiments,it is the hydrophilicity and the capillary effects of the wettabletransparent materials that can keep certain distillation liquid on thesolar panel surface against gravity even when the left end of solarhouseis lift up significantly higher than its right end until to a completelyvertical position. The wettable transparent materials that can be usedfor this application include (but not limited to): hydrophilictransparent polymer materials (e.g., hydrophilic acrylate ormethacrylate polymer), super-hydrophilic and transparent thin films ofTiO₂ nanotube arrays, transparent hydrophilic TiO₂ thin film,hydrophilic sol-gel derived SiO₂/TiO₂ transparent thin film, polyalcoholdiepoxide, polyvinylpyrrolidone and polydimethacrylamide-copolymers withpolymerizable α-unsaturated groups plus polyisocyanates and anionicsurfactants, hydrophilic polyacrylic acid network-structured materials,hydrophilic transparent resin, transparent hydrophilic paint,hydrophilic glass fibers, hydrophilic glass beads, hydrophilictransparent gel materials, hydrophilic organic transparent gel,hydrophilic cellulose thin (transparent) film, hydrophilic transparentplastic fibers, porous poly(methyl methacrylate) films, Ti-containingmesoporous silica thin films, porous transparent hydrophilic plasticfilms, and combinations thereof.

The other components of the modified photovoltaic-panel-interfacedsolarhouse 1200 (FIG. 2B) is similar to those of FIG. 2A. Briefly, thephotovoltaic panel is in communication with solar electricity outputterminals 1212 for harvesting the electrical energy generated. Theseterminals can be in communication with an electrical load or a storagesource such as one or more batteries. A heat-conducting transparentprotective plate or film 1203 is provided interfacing in between thephotovoltaic panel 1201 front surface and the wettable transparentmaterial 1204. The solarhouse system also includes an arch-shaped orcurved vapor-condensing transparent ceiling 1205 constructed from atransparent material such as transparent plastic cover and forming thetop of the solarhouse system and a plurality of walls 1206 forming thesides of the solarhouse system and supporting the transparent ceiling1205. Suitable materials for the walls 1206 include, but are not limitedto, liquid-tight and air-tight sealing materials, e.g., transparentplastic film. The distillation chamber is formed by the heat-conductingtransparent protective plate or film 1203 (on top of the photovoltaicpanel 1201 front surface) as the chamber's bottom, the walls 1206 as thechamber's sides, and the arch-shaped or curved vapor-condensingtransparent ceiling 1205 as the chamber's top. The headspace 1215 withinthe distillation chamber above the hydrophilic transparent materialwetted with distillation liquid 1204 allows vapor 1213 from thedistillation liquid to travel up to the ceiling (inner surface) to becondensed there forming condensate droplet 1214.

According to one of the various embodiments, a distillation chambersystem such as the arch-shaped distillation chamber system shown in FIG.2B is built largely from liquid-tight and air-tight sealing plasticmaterials such as transparent plastic film that are flexible. Such aliquid-tight and air-tight distillation liquid chamber can be readilyerected and maintain its erected shape using a positive inside airpressure such as by blowing in certain amount of air into thedistillation chamber. Use of this internal air pressure approach enableserection of a plastic film-made distillation chamber system such as thearch-shaped distillation chamber system (FIG. 2B) without requiring anyadditional structural material to support the weight of the distillationchamber ceiling systems. Therefore, in one of the various embodiments,it is a preferred practice to erect a plastic film-made distillationchamber system and maintain its erected shape for distillation operationby use of a positive inside air pressure.

A set of condensate-collecting ducts 1207 are provided and are locatedaround the solarhouse walls below the level of the ceiling 1205 andpreferably just below the point of intersection of the walls andceiling. The condensate-collecting ducts form a narrow channel or gutterfor collecting condensate 1214 that forms as distillation liquid vapor1213 condensing at the ceiling and then runs down the ceiling toward thewalls. At least one condensate collecting tube 1208 is provided atdistillation chamber's right end (above liquid outlet 1211) incommunication with the condensate-collecting ducts 1207 and one or morecondensate tanks 1209, linking the condensate collecting ducts to thecondensate tank. A condensate tube outlet 1216 is extended into thecondensate tank 1209. The solarhouse system also includes at least onesource liquid inlet 1210 and at least one adjustable liquid outlet 1211passing through the walls of the solarhouse system. The inlet and outletare in communication with the hydrophilic transparent material wettedwith distillation liquid 1204 within the solarhouse system. If/when thesolarhouse is tilted by lifting up its left end to a heightsignificantly higher than that of its right end, the source liquid 1210can flow down along the wettable transparent material 1204 whichtemporarily retains the liquid on the hot solar panel surface beneficialfor distillation. The condensate from the distillation, in this case,will slide down along the 1205 ceiling inside surface and the collectingduct system to the condensate collecting tube 1208 and to tank 1209 atsolarhouse's right end for condensate harvesting while co-producingsolar electricity. This designer flexibility in placing aphotovoltaic-panel-interfaced solarhouse in any desired angle can oftenhelp to maximally capture sunlight on the Earth surface. This featurealso enables deployment of the photovoltaic-panel-interfaced solarhousetechnology at many places including on level fields, on slope hillsides, and on certain roofs and walls of buildings facing sunlight toprovide both solar electricity and distillation products.

In accordance with another embodiment as illustrated in FIG. 2C, forexample, an air-erectable and floatable photovoltaic panel-interfacedsolarhouse distillation system 2200 for generating solar electricity anddistillation products on water such as sea surface comprises: anair-erectable base chamber with the insulator support plate 2202 as itstop and part of solarhouse walls 2206 below the level of photovoltaicsolar panel 2201 as its walls containing air space 2219 and condensateliquid storage space 2209; an air-erectable arch-shaped distillationchamber with a heat-conducting transparent plate/film 2203 above thephotovoltaic panel 2201 as bottom and part of solarhouse walls 2206above the level of the photovoltaic panel 2201 as its walls containingdistillation chamber liquid 2204 and chamber headspace 2215; a set ofsource liquid inlet 2210 and liquid outlet 2211 passing through thedistillation chamber wall to feed and discharge distillation liquid2204; a set of condensate collecting ducts 2207 located around thesolarhouse inner walls below the level of the ceiling 2205 andpreferably just below the point of intersection of the walls and ceilingfor collecting condensate 2214 that forms as distillation liquid vapor2213 condensing at the ceiling and then runs down the ceiling toward thewalls; an inter-chamber condensate-transporting tube 2208 that transfersthe condensate from condensate collecting duct 2207 of the distillationchamber into the base chamber condensate liquid storage space 2209below; and a set of electricity output terminals 2212 of thephotovoltaic panel 2202 for harvesting the solar electricity generated.

This system 2200 (FIG. 2C) is similar to that of FIG. 2A except its twounique features: 1) using an additional base chamber containingcondensate liquid storage space 2209 and air space 2219 as a mechanismto create and adjust floatation buoyancy so that the system floats onwater such as pond and sea surface, and 2) using an inter-chambercondensate-transporting tube 2208 that transfers the condensate fromcondensate collecting duct 2207 of the distillation chamber into thebase chamber condensate liquid storage space 2209 below. The floatationbuoyancy created by this embodiment is essential for the use of thisphotovoltaic-interfaced distillation technology on sea surface, althoughthis air-erectable and floatable photovoltaic panel-interfacedsolarhouse distillation system (FIG. 2C) can be used also on lands androof tops for co-generating solar electricity and distillation productsas well.

In accordance with another embodiment as illustrated in FIG. 2D, forexample, an air-erectable and floatable photovoltaic panel-interfacedsolarhouse distillation system 6200 for co-generating solar electricityand distillation products on seawater surface comprises: anair-erectable base chamber with the insulator support plate 6202 as itstop and part of solarhouse walls 6206 below the level of photovoltaicsolar panel 6201 as its walls containing the chamber air space 6219 andcondensate liquid storage space; an air-erectable distillation chamber6204 with a heat-conducting transparent plate/film 6203 above thephotovoltaic solar panel 6201 as its bottom and part of solarhouse walls6206 above the level of photovoltaic solar panel 6201 as its wallscontaining the distillation chamber 6204 liquid and headspace 6215; aheat-insulating side wall/layer 6277 around the solarhouse to minimizeloss of heat to the environment including the surrounding seawater; atleast one pair of source liquid inlet 6210 and outlet 6211 connected todistillation chamber 6204 at its two ends below the seawater level 6272;a set of condensate collecting ducts 6207 located around the solarhouseinner walls below the level of the ceiling 6205 and preferably justbelow the point of intersection of the walls and ceiling for collectingcondensate droplet 6214 that forms as distillation liquid vapor 6213condensing at the ceiling and then running down the ceiling toward thewalls; an inter-chamber condensate-transporting tube (not shown in FIG.2D) that collects and transfers the condensate 6214 from collecting duct6207 of the distillation chamber above photovoltaic solar panel 6201into the base chamber condensate liquid storage space 6209; and a set ofelectricity output terminals 6212 of the solar photovoltaic panel 6201for harvesting the solar electricity generated; and a condensate liquidoutlet 6228 with valve/tube connected at the bottom of the base chamberfor harvesting product liquid.

FIG. 2D presents a front view of the air-erectable and floatablephotovoltaic panel-interfaced solarhouse distillation system 6200, whichis similar to that of FIG. 2C except its additional componentscomprising a heat-insulating side wall/layer 6277 around the solarhouseto minimize loss of heat to the environment including the surroundingseawater; at least one pair of source liquid inlet 6210 and outlet 6211connected to distillation chamber 6204 at its two ends below theseawater level 6272; and a condensate liquid outlet 6228 with valve/tubeconnected at the bottom of the base chamber for harvesting productliquid. This system 6200 has the following operational features: a)using heat-insulating side walls for better energy efficiency; b)adjusting buoyancy with proper use of the base chamber air space 6219 sothat the surrounding seawater level 6272 is slightly higher than thefeed liquid level 6278 of the distillation chamber 6204 to enableautomatic source liquid feeding and discharging; c) employing, at least,one source liquid inlet 6210 valve/tube immersed under the seawaterlevel to automatically feed seawater into the distillation liquid feedchamber 6204 without requiring any external pump; d) utilizing therocking motion of solarhouse distillation chamber 6204 with ocean wavesto automatically discharge brine liquid and re-feed seawater through, atleast, one pair of source liquid inlet 6210 and outlet 6211 valves/tubesimmersed under the seawater level; e) using an inter-chambercondensate-transporting tube that collects and transfers the condensate6214 from condensate-collecting duct 6207 of the distillation chamberabove the photovoltaic solar panel 6201 into the base chamber condensateliquid storage space 6209; and f) using a condensate liquid outlet 6228valve/tube connected at the bottom of the base chamber for harvestingproduct liquid.

In practice, the buoyancy of the air-erectable and floatablephotovoltaic panel-interfaced solarhouse distillation system 6200 isadjusted with proper use of the base chamber air space 6219 so that thebottom part of the solarhouse containing the base chamber anddistillation chamber 6204 is sinking down into seawater until thesurrounding seawater level 6272 is slightly higher than the feed liquidlevel 6278 of the distillation chamber 6204. Under these conditions, theexternal seawater can be fed into the distillation chamber 6204 throughthe source liquid inlet 6210 without requiring any mechanical pump,which is a significant energy saving feature. Furthermore, since theliquid feed/discharge tubes 6210 and 6211 are connected to the liquidfeed chamber 6204 at its two opposite sides below the seawater level6272, use of the rocking motion of the solarhouse distillation chamberwith ocean waves also facilitates the release of used feed liquid(brine) into sea and the intake of fresh seawater when the valves ofliquid feed/discharge tubes 6210 and 6211 are both open. For example, asthe solarhouse system 6200 rocking left and right with ocean waves, theliquid in liquid feed chamber 6204 can flow in and out through tubes6210 and 6211, facilitating the release of the used feed liquid (brine)into sea and the intake of fresh seawater without requiring any externalpump. This is another significant feature that can save the energy costof an external pump that would otherwise be required. Note, it isimportant to control the rates for the rocking-motion-assisted releaseof used feed liquid (brine) and intake of fresh seawater. If these ratesare too high, it would result in too much liquid exchange between theliquid feed chamber 6204 and the ocean that could lead to someunnecessary heat energy loss from the feed chamber liquid into the sea.If these rates are too low, it would result in too little discharge ofthe used feed liquid (brine) into the sea that could lead to asuboptimal condition for the distillation process. Therefore, the ratesfor the rocking-motion-assisted release of used feed liquid (brine) andintake of fresh seawater are adjusted by use of the liquid inlet 6210and outlet 6211 valves to achieve optimal distillation productivitywhile synergistically co-generating solar electricity. It is also apreferred practice to use the feature of the rocking-motion-assistedrelease of used feed liquid (brine) and intake of fresh seawater atnights and perform distillation while co-generating solar electricityduring the day time.

In accordance with another embodiment as illustrated in FIG. 2E, forexample, an air-erectable and floatable photovoltaic panel-interfacedsolarhouse distillation system 3200 for co-generating solar electricityand distillation products on water such as sea surface comprises: anerectable and floatable distillation solarhouse containing aphotovoltaic panel-based distillation chamber 3204 with its top open(mouth) to allow vapor 3213 to reach the vapor-condensing andtransparent distillation solarhouse wall and ceiling 3205; a basechamber air space 3219 that acts as part of a floatation buoyancymechanism and separates the bottom-insulated photovoltaic panel (3201with insulator 3202) from the base chamber condensate liquid space; atransparent wall and splashing-resistant baffle 3250 around anevaporative distillation chamber 3204 mouth to prevent the distillationliquid from spilling out into the base chamber condensate liquid storagespace; and an inner inter-space 3260 between the distillation chamberwall/baffle 3250 and the solarhouse (outer) wall 3205 to allowcondensate droplets 3214 to slide from the distillation house ceilingand wall 3205 down into the base chamber condensate liquid accumulationspace.

This system 3200 (FIG. 2E) is similar to the embodiment illustrated inFIG. 2C and shares many common structures with that embodiment. A uniquefeature of this embodiment 3200 (FIG. 2D) is that this system uses aninner inter-space 3260 (between the distillation chamber wall and thesolarhouse outer wall) through which the condensate droplets 3214 canflow along the inner surfaces of the solarhouse ceiling and walls 3205directly into the base chamber condensate liquid accumulation space 3209without requiring the use of any condensate collection ducts and tubes.According to one of the various embodiments, the inner inter-space 3260is preferably to be an opening of about 2-20 mm (between thedistillation chamber wall and the solarhouse wall) so that thecondensate droplets 3205 from the inner surface of the distillationceiling/wall can readily flow down through the opening into the basechamber condensate liquid storage space at the bottom. Furthermore, thedistillation chamber in this embodiment is largely open at its top mouthand a set of tilted baffle 3250 is used around the evaporativedistillation chamber 3204 mouth to prevent distillation liquid fromspilling out into the base chamber condensate liquid storage space.Therefore, this system 3200 can be employed for making distilled waterwhile co-generating electricity on water such as sea surface with wavesand tides. Although it is designed for use on water, the embodimentsystem 3200 can be used also on lands and roof tops as well. FIG. 2Epresents a front view of the air-erectable and floatable photovoltaicpanel-interfaced solarhouse distillation system using a base chamber airspace and inner inter-spaces between distillation chamber wall andsolarhouse (outer) wall for generating solar electricity anddistillation products on water, sea surface, and/or on lands and rooftops.

In accordance with another embodiment as illustrated in FIG. 2F, forexample, an air-erectable and floatable photovoltaic panel-interfacedhydrophobic microporous plate distillation system 4200 is provided forgenerating solar electricity and distillation products on water such assea surface. This system 4200 comprises: a solar photovoltaic panel 4201with electricity output terminals 4212 and with a heat-conductingplate/film 4203 as its back surface, a liquid feed chamber 4204 withheat-conducting plate/film 4203 as its top and a hydrophobic microporousplate/membrane 4270 as its bottom, a source liquid inlet 4210 and aliquid outlet 4211 connected to the two ends of liquid feed chamber4204, a base condensation chamber that contains air space 4219 andcondensate liquid space 4209, and solarhouse walls 4206 that join withheat-conducting plate/film 4203 and hydrophobic microporous plate 4270forming the two chambers separated by the hydrophobic microporous plate4270 in between: the liquid feed chamber 4204 and the base condensationchamber containing liquid space 4209 and air space 4219.

This system 4200 (FIG. 3F) is somewhat similar to that of FIG. 2C withthree similarities and six unique features. The three similarities are:a) The distillation in both of the two systems (4200 and 2200) utilizeswaste heat from a photovoltaic panel; b) A similar base chamber airspace is used as a floatation buoyancy mechanism in both systems so thatthey floats on water such as on pond water and/or sea surface; and c)Both of these air-erectable and floatable photovoltaic panel-interfaceddistillation systems (FIGS. 2F and 2C) can be used on water such as seasurface as well on lands and roof tops for co-generating solarelectricity and distillation products. The six unique features of thesystem 4200 (FIG. 2F) are: 1) This embodiment uses a liquid feed chamber4204 which uses a heat-conducting plate/film 4203 underneathphotovoltaic panel 4201 as its top and a hydrophobic microporous plate4270 as its bottom; 2) Its base (bottom) condensation chamber uses thehydrophobic microporous plate 4270 as its top so that the system canperform a type of hydrophobic microporous plate distillation; 3) The topsurface of solar photovoltaic panel 4201 can directly face the sun toreceive light without any shading effect; 4) It uses a base condensationchamber that contains air space 4219 and condensate liquid space 4209;5) It uses a special type of hydrophobic microporous plate membranedistillation; 6) In this case, it is a preferred practice to use ananti-reflection heat-insulating transparent plate/film 4233 on the topsurface of solar photovoltaic panel 4201 for better energy efficiency.

In accordance with one of the various embodiments, the hydrophobicmicroporous plate 4270 with low surface energy comprises certainhydrophobic polymer membrane materials that are selected from the groupconsisting of polypropylene (PP), polytetrafluoroethylene (PTFE),polyvinylidene fluoride (PVDF), and polyethelene (PE).

According to another embodiment, the hydrophobic microporous plate 4270comprises a hydrophobic microporous membrane constructed on a porousplate support material. The hydrophobic microporous membrane is madefrom hydrophobic polymer materials that are selected from the groupconsisting of polypropylene (PP), polytetrafluoroethylene (PTFE),polyvinylidene fluoride (PVDF), polyethelene (PE), and combinationsthereof. The support plate material is selected from the groupconsisting of porous carbon fiber plates, porous glass fiber plates,porous plastic plates, fiberglass-reinforced plastic materials, carbonfiber composite materials, vinyl ester, epoxy materials, porouspolytetrafluoroethylene plates, polytetrafluoroethylene is commerciallyavailable under the tradename Teflon from Chemours of Wilmington, Del.,porous glass plates, porous aluminum plates, porous stainless steelplates, and combinations thereof. Hydrophobic microporous membranes canbe made with a number of techniques known in the field. For example,microporous PP membranes are commonly prepared by a thermally inducedphase separation process while microporous PVDF membrane are constructedby the dry/wet spinning technique. It is a preferred practice to placeor construct a hydrophobic microporous membrane on a support platematerial to provide sufficient mechanical strength for practical use ofthe so-formed plate membrane, which is totally hydrophobic or at leastits layer facing the liquid feed is hydrophobic.

In operation, the solar photovoltaic panel 4201 passes its waste heatthrough a heat-conducting plate/film 4203 to heat up the feed liquid inchamber 4204 while the bottom part of solarhouse distillation chamberwalls 4206 is cooled by its surrounding air and/or seawater in theenvironment. The heat in the feed liquid vaporize its water at theentrance of the hydrophobic membrane pores at the feed liquid side ofthe hydrophobic microporous plate 4270; and the water vapor passesthrough the hydrophobic membrane pores entering the condensation chamberwhere water vapor 4213 condenses onto a hydrophilic inner wall surfaceof the base condensation chamber forming condensate droplets 4214 and/orcondenses directly into the cooled condensate liquid 4209 at the bottomof the chamber. The inner wall surface of the base condensation chamberpreferably is highly hydrophilic to facilitate the water vaporcondensation process there. The condensate droplets 4214 are collectedas they slide down along the wall surface with gravity into thecondensate liquid 4209 at the bottom of the base condensation chamber asshown in FIG. 2F.

The driving force for hydrophobic microporous plate distillation is thedifference in temperature between the feed liquid 4204 and thecondensate liquid 4209, which in turn drives their difference in partialpressure of water vapor across the hydrophobic microporous plate 4270membrane. The hydrophobic microporous plate and/or membrane must behighly hydrophobic and microporous with high void volume or porosity.The hydrophobic nature of the membrane prevents the feed liquid 4204 topenetrate into the membrane pores creating vapor-liquid interfaces atthe entrance of the membrane pores. The liquid feed pressures aretypically near ambient atmospheric pressure in this case. Under theseconditions, water molecules evaporate at the hot liquid/vapor interface,flow across the membrane pores in vapor phase, and finally enter thecold base condensation chamber to be condensed for production ofdistilled water. Since the salts in the feed liquid 4204 (such asseawater or brine) are not vaporized in this process, the product waterfrom this hydrophobic microporous plate membrane distillation istypically in excellent quality, which is essentially free of any salts.The product water quality can be measured by its electrical conductivityand/or total dissolved salts content. In this example, the electricalconductivity of product water from photovoltaic-interfaced hydrophobicmicroporous plate membrane distillation is typically about 1 microSiemens per centimeter (μS/cm) and its total dissolved salts content isless than 1 mg per litter.

According to one of the various embodiments, the membrane pore sizes andthickness are specially selected so that the membrane pores are notwetted by the feed liquid with sufficiently high liquid entry pressureto ensure that the hydrophobic microporous plate 4270 will not let anyfeed liquid (such as seawater) to leak through the membrane pores. It isthe surface tension of the feed liquid at the entrance of thehydrophobic membrane pores that prevents the salts-containing feedliquid from leaking through the membrane pores. The hydrophobic membranepores can, however, allow water vapors to pass through and enter thebase condensation chamber air space 4219. Since the salts in the feedliquid such as seawater are not vaporized under these conditions, thehydrophobic microporous plate distillation process can achieve very highsalts rejection, which can be as high as close to 100%. The water vapors4213 emerging from the bottom surface of hydrophobic microporous plate4270 travel through the base condensation chamber air space 4219 andcondense onto the chamber inner wall surfaces and/or into the cooledcondensate liquid 4209 at the bottom of the condensation chamber. Thecondensate in this example is distilled water, which can be readilyharvested.

According to one of the various embodiments, the membrane pore sizes ofhydrophobic microporous plate 4270 are preferably in a range fromseveral nanometers to a few micrometers, which is significantly biggerthan that used for reverse osmosis desalination that requires a membranepore size typically no more than about 1 nanometer. The hydrophobicmembrane pore sizes should be selected in consideration with theassociated membrane thickness and feed liquid pressure. Under relativelymoderate liquid feed pressure (close to ambient pressure), a larger poresize may be used with a thicker hydrophobic membrane. The water-vaporpermeate flux increases along with an increase in the membrane porosity.If the membrane pore size is too large, however, the feed liquid surfacetension at the entrance of membrane pores may become insufficient toovercome the liquid pressure to prevent from wetting of the membranepores, which could negatively affect the salt rejection efficiency inthe membrane distillation process. On the other hand, if the membranepore size is too small, it could become more susceptible to fouling andlimit the membrane distillation productivity. Therefore, the hydrophobicmembrane pore sizes are preferably selected from the group consisting of8 micrometers (μm), 6, μm, 5 μm, 4 μm, 3 μm, 2 μm, 1.5 μm, 1.0 μm, 0.8μm, 0.6 μm, 0.5 μm 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.05 μm, 0.02 μm,0.01 μm, 0.005 μm, and/or within a range bounded by any two of thesevalues. Since the water vapor permeate flux across a hydrophobicmembrane typically is inversely proportional to membrane thickness, athin hydrophobic membrane is preferred to achieve high processproductivity. However, if a hydrophobic membrane is too thin, it couldbecome more susceptible to wetting with fouling that could result inundesirable process stability and reduced salt-rejection efficiency.Furthermore, according to one of the various embodiments, thehydrophobic membrane must have certain thickness to provide sufficientmechanical strength in certain meters-size plate geometry to hold thebulk liquid of the liquid feed chamber without collapsing. Use ofsupport plate materials with hydrophobic membranes as disclosed abovecan enhance the mechanical strength for practical use. Therefore, thehydrophobic membrane thickness is preferably selected from the groupconsisting of 10 millimeters (mm), 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.8 mm,0.6 mm, 0.4 mm. 0.2 mm, 0.1 mm, 0.05 mm, 0.02 mm, and/or within a rangebounded by any two of these values. The salt rejection in thehydrophobic microporous plate distillation is preferably over 99%, morepreferably over 99.9%, and, most preferably, over 99.99%.

In accordance with one of the various embodiments, the hydrophobicmicroporous plate distillation rate is measured as the permeate flux,which is the rate of water vapor mass transfer across the hydrophobicmembrane through the gas phase in membrane pores per unit membrane area.The permeate flux depends on a number of factors, which include themembrane thickness and pore size, the source liquid salts concentration,and the temperature difference between the hot liquid feed 4204 and thecooled condensate liquid 4209. For example, when solar photovoltaicpanel 4201 passes its waste heat across a heat-conducting plate/film4203 to heat the feed liquid in chamber 4204 while the base condensationchamber walls 4206 is cooled typically by its surrounding seawater incontact. The temperature difference between the hot feed liquid and thecooled condensate liquid can be at a value selected from the groupconsisting of 0.1° C., 0.2° C., 0.5° C., 1° C., 2° C., 3° C., 4° C., 5°C., 6° C., 8° C., 10° C., 15, 20° C., 25° C., 30° C., 35° C., 40° C.,45° C., 50° C., 60° C., 70° C., 80° C., and/or within a range bounded byany two of these values. The heat in the liquid feed vaporize its waterat the entrance of hydrophilic membrane pores; and the water vaporpasses through the membrane pores entering the base condensation chamberwhere water vapor 4213 condenses forming product water (condensate). Theproductivity of hydrophobic microporous plate membrane distillation ispreferably maintained at a level selected from the group consisting ofmore than 0.5 liter of product water per square meters of membrane perday (L/m² day), 0.6 L/m², 1 L/m², 2 L/m², 4 L/m² day, 6 L/m² day, 8 L/m²day, 10 L/m² day, 12 L/m² day, 14 L/m² day, 16 L/m² day, 18 L/m² day, 20L/m² day, 30 L/m² day, 60 L/m² day, 120 L/m² day, and/or within a rangebounded by any two of these values. The hydrophobic microporous platedistillation energy efficiency is measured as the thermal efficiency,which can be at a level selected from the group consisting of 10%, 20%,30%, 40%, 50%, 60%, 70%, 80%, and/or within a range bounded by any twoof these values.

In accordance with another embodiment as illustrated in FIG. 2G, forexample, an air-erectable and floatable photovoltaic panel-interfacedhydrophobic microporous plate membrane distillation system 5200 forco-generating solar electricity and distillation products on water suchas sea surface comprises: a solar photovoltaic panel 5201 with aheat-conducting plate/film 5203 as its back surface and with electricityoutput terminals 5212; a liquid feed chamber 5204 with heat-conductingplate/film 5203 as its top and a hydrophobic microporous plate/membrane5270 as its bottom; at least one pair of energy-saving liquidfeed/discharge tubes 5210 and 5211 connected to the two opposite sidesof liquid feed chamber 5204; a base condensation chamber that containsair space 5219 and condensate liquid space 5209; a hydrophobicmicroporous plate membrane 5270 which serves as the bottom of liquidfeed chamber 5204 and also as the top of the base condensation chamberthat contains its condensate liquid and air space 5219; solarhouse walls5206 that join with heat-conducting plate/film 5203 and hydrophobicmicroporous plate membrane 5270 forming the liquid feed chamber 5204 andthe base condensation chamber containing liquid and air space 5219; anda condensate outlet 5228 connected to the bottom of the basecondensation chamber for harvesting product liquid.

In the practice of this exemplary embodiment, the liquid feed (such asseawater) in chamber 5204 is heated (by the waste heat from solar panel5201) to increase its vapor pressure, which generates the difference inpartial pressure between two sides of hydrophobic microporous plate5270. Hot water evaporates through nonwetted pores of hydrophobicmicroporous plate 5270 membrane, which cannot be wetted by the aqueoussolution in contact with and only vapor and noncondensable gases shouldbe present within the membrane pores. The passed vapor is then condensedforming condensate droplet 5214 on the condensation chamber inner wallsurface and/or condensed into the cooler condensate liquid at the bottomof the chamber as shown in FIG. 2G. The condensate can be readilyharvested as product water through the use of condensate outlet 5228.

This system 5200 (FIG. 2G) is similar to the one illustrated in FIG. 2Fand shares many common structures with that embodiment. In this example,the bottom part (base condensation chamber) of the system 5200 isimmersed in seawater which is typically cooler than the hot feed liquidchamber 5204 at the upper part of system 5200. The distance H5271between the photovoltaic panel top surface and the seawater level 5272can be adjusted by controlling the volume of air injected into the airspace of the air-erectable base condensation chamber in adjusting thebuoyancy for the entire photovoltaic panel-interfaced hydrophobicmicroporous plate distillation system 5200. The distance H5271 can be ata value selected from the group consisting of 0 cm, 1 cm, 2 cm, 3 cm, 5cm, 10 cm, 20 cm. 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm 100cm, 120 cm, 150 cm, 200 cm, 300 cm, 500 cm, and/or within a rangebounded by any two of these values.

A unique feature of system 5200 (FIG. 2G) is that this embodiment usesat least one pair of energy-saving liquid feed/discharge tubes 5210 and5211 that are connected with the liquid feed chamber 5204 at itsopposite sides. After the liquid feed chamber 5204 is fully filled up(leaving no air bubbles in the liquid feed chamber system), theenergy-saving liquid feed/discharge tube ends 5210 and 5211 are keptimmersed under seawater level 5272. Use of the energy-saving liquidfeed/discharge tubes 5210 and 5211 in this manner enables automaticfeeding of seawater into the liquid feed chamber 5204 without requiringany external pump. In practice, when the water potential (pressure) inliquid feed chamber 5204 is reduced by the removal of water throughphotovoltaic panel-interfaced hydrophobic microporous plate membranedistillation, the external source seawater will be automatically suckedup through energy-saving liquid feed/discharge tube 5210 into the liquidfeed chamber 5204 for continued membrane distillation without requiringany external mechanical pump. The fundamental scientific mechanismbehind this innovative feature is somewhat similar to the“transpiration” effect by which a higher plant such as a tree pullswater from soil all the way up to its leaves at the top of the tree. Ina tree, as water evaporates through its leaves with stomata (micropores) into air, it reduces the water potential in the leaves, which inturn pulls water from soil through its roots and stem with xylems (microtubes) all the way up into the tree leaves at the top. The hydrophobicmicroporous plate 5270 membrane of liquid feed chamber 5204 in thepresent embodiment acts like a leaf surface; As water in liquid feedchamber 5204 evaporates through the hydrophobic membrane pores into theair space 5219 of the condensation chamber as illustrated in FIG. 2G, itreduces the water potential (pressure) in the liquid feed chamber 5204,which in turn pulls external seawater all the way up through theenergy-saving liquid feed/discharge tube 5210 into the liquid feedchamber 5204. Use of this “transpiration”-like mechanism withhydrophobic microporous plate membrane distillation can typically pullseawater up to a height as much as about 500 cm from the seawater level,which is consistent with the range of H5271 values disclosed above.Therefore, this is a significant feature that can save the energy costof an external pump that would otherwise be required.

According to one of the various embodiments, a balanced H5271 value ispreferably selected to also control/adjust the internal pressure in theliquid feed chamber 5204 so that the liquid feed will not penetratethrough a hydrophobic microporous plate/membrane 5270; neither would theproperly adjusted internal pressure allow any air gas from the air space5219 at the other side to break/flow through the water surface tensionbarrier at the hydrophobic microporous plate 5270 membrane pores.

When the photovoltaic panel-interfaced hydrophobic microporous platedistillation system 5200 is used on sea surface with its flotationfeature, the entire distillation system may rock with ocean waves. Asshown in FIG. 2G, energy-saving liquid feed/discharge tubes 5210 and5211 are connected with the liquid feed chamber 5204 at its left andright sides. Additional energy-saving liquid feed/discharge tubes can beconnected to the front and back sides of the liquid feed chamber 5204 aswell. Since the energy-saving liquid feed/discharge tubes 5210 and 5211that are connected with the liquid feed chamber 5204 at the two oppositesides, use of the rocking motion can facilitate the release of used feedliquid (brine) into sea and the uptake of fresh seawater when the valvesof energy-saving liquid feed/discharge tubes 5210 and 5211 are bothopen. For example, as the solarhouse system 5200 rocking left and right(or back and forwards) with ocean waves, the liquid in chamber 5204 canflow in and out through the tubes 5210 and 5211 (or through additionaltubes mounted at the front and back sides of liquid feed chamber 5204),facilitating the discharge of used feed liquid (brine) into sea and theuptake of fresh seawater into liquid feed chamber 5204 without requiringany external pump. This is another significant feature that can save theenergy cost of an external pump that would otherwise be required. Therates for the rocking-motion-assisted release of used feed liquid(brine) and intake of fresh seawater are adjusted by adjusting theliquid inlet 5210 and outlet 5211 tube valves for optimal distillationproductivity while synergistically co-generating solar electricity.

Under certain environmental and/or weather conditions, the temperatureof the liquid feed chamber 5204 at certain time such as at night maybecome lower than that of the base chamber condensate liquid so that themembrane distillation process could undesirably run in the reversedirection across the hydrophobic microporous plate 5270 membrane,resulting in loss of condensate liquid from the condensation chamber tothe liquid feed chamber 5204. According to one of the variousembodiments, this technical problem is solved by promptly harvesting thecondensate liquid (distilled water) through the use of condensate outlet5228 at the end of each day before a reversal temperature gradientacross hydrophobic microporous plate 5270 membrane could occur at night.Another way to minimize this problem is by circulating seawater throughthe liquid feed chamber 5204 using the feature of therocking-motion-assisted release of used feed liquid (brine) and intakeof fresh seawater at nights, which can minimize the possible temperatureinversion between the liquid feed chamber 5204 and the base condensationchamber.

In accordance with another embodiment as illustrated in FIG. 3, forexample, a photovoltaic panel-interfaced distillation solarhouse system300 is provided as an arch-shaped distillation liquid chamber system.This embodiment is similar to the embodiment illustrated in FIG. 2A andshares many common structures with that embodiment. In addition, thisembodiment includes a sea water inlet 310 that introduces sea water orbrine into a brine salt-making distillation liquid 304 of the system anda brine outlet 311 to remove the concentrated or used residual brine.The system also includes a flexible air pump feeding system 316 incommunication with the brine salt-making distillation liquid and thevapor 213 space (also as the chamber headspace 215) above thedistillation liquid to provide for dry air feeding into the system. Atail gas condensing system 317 is provided having a tail gas exit pipe318 passing through the ceiling 205 in communication with thedistillation chamber headspace 215, a condensate outlet 319 and a vent320. The tail gas condensing unit collects vapor from the vaporheadspace 215 above the distillation liquid, condenses and collects thewater and vents the gases or air.

The distillation solar-greenhouse/chamber can be built from a number ofmaterials including, but not limited to, glass, transparent plastics andpolymer materials. As shown in FIG. 1, a heat-conducting transparentprotective plate or film 103, for example a transparent plastic film ormembrane, preferably with anti-reflection materials, is placed on top ofthe photovoltaic-panel 101 front surface, i.e., solar heat source, tointerface with the distillation chamber liquid 104, which acts as animmediate heat sink. This heat-conducting transparent plate or film 103separates and protects the photovoltaic panel 101 from the distillationchamber liquid 104 while allowing both sunlight and heat conduction topass through to the photovoltaic panel. In one embodiment, theheat-conducting but electrically insulating transparent plate or filmmembrane 103 is made from a plurality of thermally conductivetransparent materials selected from the group consisting of colorless,i.e., clear, transparent plastics, for example, Acrylic(polymethlamethacrylate), Butyrate (cellulose acetate butyrate), Lexan(polycarbonate), and PETG (glycol modified polyethylene terphthalate),polypropylene, polyethylene, and polyethylene HD, thermally conductivetransparent plastics, colorless and transparent conductive paint,colorless glass, borosilicate glass which is commercially available asPyrex-glass from Corning Company of Corning, N.Y., sol-gel, siliconerubber, quartz mineral, transparent cellulose nanofiber/epoxy resinnanocomposites, glass-ceramic materials, transparent ceramics, cleartransparent plastics containing anti-reflection materials and/orcoating, clear glass containing anti-reflection materials or coatingsand combinations thereof.

In accordance with any of the embodiments illustrated herein, certainclear transparent plastics films or membranes are used to make an entiredistillation liquid chamber including its bottom wall interfacing withthe photovoltaic panel front (top) surface. Although some of thesetransparent materials may have certain limited thermal conductivity,they or their combination can be used to make a relatively thin plate,film or membrane so that it can conduct heat at a reasonable rate withlittle heat buildup in the photovoltaic panel. The distillation liquidserves as an immediate heat sink that utilizes the solar waste heat tovaporize the liquid for distillation.

Heat buildup in the electronic components of a photovoltaic panel canseverely limit service life and reduce operating efficiency. Use ofcertain injection moldable and extrudable heat-conducting transparentplastic compounds known as thermally conductive plastics can alsoprovide significant benefits in solar waste heat management andutilization in accordance with exemplary embodiments of the presentinvention. Certain heat conductive transparent plastics are speciallymade by compounding certain heat conductive fillers, for example certaintransparent ceramics, with polymers. The added heat-conducting fillerseliminate hot spots in components by spreading out the heat more evenlythan unfilled plastics. Their inherently low coefficient of thermalexpansion lowers their shrink rates and helps replace certain metals,glasses, and ceramics in dimensionally critical parts. Other advantagesof the materials include design flexibility, corrosion and chemicalresistance and reduction of secondary finishing operations inmanufacturing of the photovoltaic-panel-interfaced solar-greenhousedistillation systems.

In one embodiment, the heat-conducting transparent plate, film ormembrane is made from a wide range of heat-conducting transparentmaterials that are selected from the group consisting of colorlessglass, borosilicate glass, sol gel, silicone rubber, quartz mineral,transparent cellulose nanofiber/epoxy resin nanocomposites,glass-ceramic, transparent ceramics and combinations thereof. Many ofthe commercially available photovoltaic panels or modules often have asheet of protective glass on the front, i.e., sun up, side, allowinglight to pass while protecting the semiconductor wafers fromenvironmental elements such as rain, hail and dusts. Therefore, many ofthe commercially available photovoltaic panels can be used to serve asthe base of a distillation liquid chamber for construction of certainsolar-greenhouse distillation systems as well without the use of anadditional heat-conducting transparent plate. However, application of anadditional protective heat-conducting transparent plate or film withspecial surface properties such as non-sticking, anti-reflection, e.g.,silicon nitride or titanium dioxide, and chemical resistance propertiesas well as resistance to mechanical damage provides added benefits forcertain solarhouse distillation operations such as the making of seasalt from seawater while co-generating solar electricity as illustrated,for example, in the embodiment of FIG. 3.

In one embodiment, the transparent vapor-condensing solarhouse ceilingis made from a number of transparent materials selected from the groupconsisting of colorless or clear transparent plastics, such as Acrylic(polymethlamethacrylate), Butyrate (cellulose acetate butyrate), Lexan(polycarbonate), and PETG (glycol modified polyethylene terephthalate),polypropylene, polyethylene (or polyethene) and polyethylene HD,thermally conductive transparent plastics, colorless and transparentconductive paint, colorless glass, borosilicate glass, sol gel, siliconerubber, quartz mineral, transparent cellulose nanofiber/epoxy resinnanocomposites, glass-ceramic materials, transparent ceramics, cleartransparent plastics containing certain anti-reflection materials orcoatings, clear glass containing certain anti-reflection materials orcoatings and combinations thereof.

According to one embodiment, an insulating base support material ispreferably used on the back or bottom of the photovoltaic panel. Thismaterial can also be used on certain side walls of the system andgenerally lessens the heat loss through conduction. Suitable insulationmaterials include, but are not limited to, polyurethane foam, Styrofoamand mineral wool. In addition, alternative insulating foam and materialscan also be used including, but not limited to, biomass fibers,softwoods, straw insulation and mineral fiber insulating materials likevermiculite, glass wool, rock wool, glass fiber or fiberglass. Typicalframe structure materials include, but are not limited to, plasticmaterials, fiberglass-reinforced plastic materials, carbon fibercomposite materials, vinyl ester, epoxy materials, wood, aluminum, steeland combinations thereof.

According to one embodiment, the photovoltaic panels include, but arenot limited to, semiconductor photovoltaic panels made frommonocrystalline silicon, polycrystalline silicon, amorphous silicon,cadmium telluride, copper indium selenide/sulfide and combinationsthereof. A wide variety of solar photovoltaic cells are suitable for usewith exemplary embodiments of the present invention. The applicablesolar photovoltaic cells panels include, but are not limited to, thinfilm solar cell panels, e.g., such as silicon thin-film cells panels,cadmium telluride photovoltaic panels, copper indium gallium selenidesolar cell panels, multijunction photovoltaic cell panels, e.g., theGaAs based multijunction devices and the triple junction GaAs solarcells panels, dye-sensitized solar cells panels, organic/polymer solarcells panels, photovoltaic shingles, photovoltaic paint panels, andcombinations thereof.

In one embodiment, use of solar photovoltaic panel-interfaceddistillation solarhouse systems can perform distillation for a number ofliquids including, but not limited to, seawater, brackish water, salinewater, brine liquid, surface water, groundwater, well-water,photobiological liquid culture media, beer, methanol solutions, ethanolsolutions, propanol (e.g., n-propanol and/or isopropyl alcohol)solutions, 1-hydroxy-2-propanone solutions, butanol (includingn-butanol, isobutanol, sec-butanol, and/or tert-butanol) solutions,cyclohexanol solutions, tert-amyl alcohol, pentanol solutions,hexadecan-1-ol solutions, polyhydric alcohols [e.g., ethane-1,2-diol(Ethylene Glycol), propane-1,2,3-triol (Glycerin),butane-1,2,3,4-tetraol (Erythritol), pentane-1,2,3,4,5-pentol (Xylitol),hexane-1,2,3,4,5,6-hexol (Mannitol, Sorbitol),heptane-1,2,3,4,5,6,7-heptol (Volemitol), solutions, unsaturatedaliphatic alcohols, e.g., prop-2-ene-1-ol (Allyl Alcohol),3,7-dimethylocta-2,6-dien-1-ol (Geraniol), prop-2-in-1-ol (PropargylAlcohol)] solutions, alicyclic alcohols [e.g.,cyclohexane-1,2,3,4,5,6-geksol (Inositol),2-(2-propyl)-5-methyl-cyclohexane-1-ol (Menthol)] solutions, primaryalcohol solutions, higher alcohols solutions, aldehyde solutions,aldehyde hydrate solutions, carboxylic acids solutions, lactosesolutions, biomass-derived hydrolysate solutions, glucose solutions,fructose solutions, sucrose solutions, furanose solutions, pyranosesolutions, monosaccharides, such as trioses, tetroses, pentoses, andhexoses, solutions, oligosaccharides solutions, polysaccharidessolutions, acetic acid solutions, propionic acid solutions, citric acidsolutions, lactic acid solutions, acetone solutions, and other organicsolutions or solvents and combinations thereof.

In operation of the embodiments of the solarhouse distillation systemsof the present invention, a distillation source liquid is introducedthrough the inlet and into an area or chamber located immediately abovea solar photovoltaic panel, proving thermal contact through theheat-conducting transparent plate or film with the photovoltaic panel.As shown in the various embodiments of the present invention, the bottomsurface of the heat-conducting transparent plate or film is preferablyin direct physical contact with the front (top) surface of thephotovoltaic panel, while the top surface of the heat-conductingtransparent plate or film is in contact with the distillation liquid. Asa result, as sunlight or solar radiation passes through theheat-conducting transparent film or plate to drive photovoltaicelectricity generation with co-production of heat at the photovoltaicpanel, the solar heat co-produced from the photovoltaic panel istransferred through a nearly one-dimensional heat conduction/flow acrossthe heat-conducting transparent film or plate into the distillationliquid above the photovoltaic panel. Subsequently, the transferred heatvaporizes the distillation liquid. This vapor rises in the chamberheadspace and condenses onto the vapor-condensing transparent tilted orarched ceiling that is cooled by air, winds and thermo infra-redradiation to the ambient environment or outer space.

Referring to FIG. 4, another exemplary embodiment of a photovoltaicpanel-interfaced distillation solarhouse system 400 in accordance withthe present invention is illustrated. The photovoltaic panel-interfaceddistillation solarhouse system is a sealed distillation liquid chambersystem that includes a bottom- or back-insulated solar photovoltaicpanel 401 mounted on an insulator base 402 constructed of a supportmaterial. The photovoltaic panel is in communication with solarelectricity output terminals 412 for harvesting the electrical energygenerated. These terminals can be in communication with an electricalload or a storage source such as one or more batteries. Aheat-conducting transparent protective plate or film is providedinterfacing in between the photovoltaic panel 401 front surface and thedistillation chamber liquid 404, which as illustrated is saline or brinedistillation liquid or saline and/or brine photobiological culture,e.g., algal culture. The solarhouse system also includes a tilted orangled vapor-condensing transparent ceiling 405 constructed from atransparent material such as transparent plastic cover and forming thetop of the solarhouse system and a plurality of walls forming the sidesof the solarhouse system and supporting the transparent ceiling 405. Theliquid distillation chamber is formed by the heat-conducting transparentprotective plate or film (on top of the photovoltaic panel 401 frontsurface) as its bottom surface, the solarhouse walls as its side walls,and the tilted or angled vapor-condensing transparent ceiling 405 as itstop. The headspace 415 within the distillation chamber above thedistillation liquid 404 allows vapor 413 from the distillation liquid totravel up to the ceiling (inner surface) to be condensed there formingcondensate droplet.

A set of condensate-collecting ducts are provided and are located aroundthe solarhouse walls below the level of the ceiling 405 and preferablyjust below the point of intersection of the walls and ceiling. Thecondensate-collecting ducts form a narrow channel or gutter forcollecting condensate that forms as distillation liquid vapor 413condensing at the ceiling and runs down the ceiling toward the walls. Atleast one condensate collecting tube is provided in communication withthe condensate-collecting ducts and one or more condensate tanks 409,linking the condensate collecting ducts to the condensate tank. Thesolarhouse system also includes at least one source liquid inlet 410 andat least one adjustable liquid outlet 411 passing through the walls ofthe solarhouse system. The inlet and outlet are in communication withthe distillation liquid 404 within the solarhouse system. The adjustableliquid outlet extends from the walls of the solarhouse system up to aheight H6 that is higher than the level of the distillation liquid 404.The liquid outlet 411 extended from the distillation chamber isadjustable through the height H6 above the photovoltaic panel.

The system 400 also includes a CO₂ source feeding system 419 incommunication with the distillation liquid and the vapor space above thedistillation liquid to provide for CO₂ gas feeding into the system. Atail gas condensing system 417 is provided having a tail gas exit pipe431 passing through the ceiling 405 in communication with thedistillation chamber vapor headspace 415, a condensate outlet 432 and avent 433. The tail gas condensing unit collects vapor from thedistillation chamber vapor headspace above the distillation liquid,condenses and collects the water and vents the vapor-removed gases.

In this embodiment, the vapor-condensing transparent ceiling 405 isactively cooled by running cold water through a water-chamber system 418disposed on top of the ceiling 405. At least one cold water inlet 420 isprovided to introduce cold water at the desired temperature into thewater-chamber 418. The cold water that is circulated through thewater-chamber 418 is collected through a plurality of water outlets 421,422. Depending on the surface property of the ceiling material, thetilted-ceiling angle α should be at least above about 5 degrees,preferably about 15 degrees to about 30 degrees, and more preferablyabout 30 degrees to about 70 degrees at all inner surface areas of theceiling to prevent condensate droplets from free falling from theceiling surface back into the distillation liquid 404 below. In thisway, as the vapor 413 condenses at the ceiling, the condensate dropletsslide downwards along the inner surface of the tilted ceiling 405 andfinally flow into the collecting ducts around the solarhouse(distillation chamber) wall by use of the surface tension and the forceof gravity. The collected condensate is then transported through acondensate-transferring tube by use of gravity to the storage tank 409.Alternatively, the condensate is passed in series to anotherdistillation solarhouse for re-distillation as is illustrated insubsequent embodiments until the desired results are achieved with thefinal distillate(s).

In general, a significant amount, for example, nearly about 85%, of thesunlight energy is dissipated as heat at a solar photovoltaic panel.This solar waste heat can be used to raise the temperature of thedistillation chamber liquid to a range of about 30° C. to about 70° C.,depending on the geographic locations and seasonal variations. This heatand the resultant temperature are sufficient to vaporize many volatilesubstances or solvents such as ethanol and water from the distillationchamber. The vapor is condensed onto the inner surface of thesolarhouse's ceiling which is transparent and can be cooled actively orpassively by the ambient air and winds, and by thermo infra-redradiation to the ambient environment. As the vapor condenses, thecondensate grows into small droplets that slide downwards along theinner surface of the tilted or arched ceiling and flow into thecollecting ducts around the solarhouse wall under the forces of surfacetension (ceiling surface-condensate droplet interaction) and gravity.For certain volatile substances such as ethanol, its concentration inthe condensate is significantly higher than that in a distillationsource beer liquid (typically 0.1-10% ethanol), because theethanol-to-water ratio in the vapor is usually greater than that in theliquid medium. Therefore, use of the systems in accordance with thepresent invention enables harvesting of volatile substances such asethanol from a distillation source liquid using solar waste heat whileco-producing solar electricity.

When a volatile solvent such as water or an organic solvent, e.g.,ethanol or methanol, is removed from the solar distillation liquid byevaporation, non-volatile solutes, including salt and sugar, remain inthe solarhouse distillation chamber. Consequently, as the photovoltaicpanel-interfaced evaporation/distillation process progresses, theconcentration of the non-volatile solute increases until a point ofsolute saturation and resultant precipitation. Therefore, the solarphotovoltaic panel-interfaced distillation technology also concentratesand harvests nonvolatile substances.

Heat generated from the photovoltaic panels raises the temperature ofthe distillation liquid to as high as about 30-70° C. Therefore, in oneembodiment, heat-tolerant photovoltaic panels are used for simultaneoussolar electricity generation and solar heat-driven distillation formaximal energy efficiency and production benefits. For certainsunlight-concentrating photovoltaic panel-interfaced solarhousedistillation systems, as illustrated, for example, in FIG. 6, thatoperates above about 100° C., a highly heat-tolerant (HT) solarphotovoltaic panel is preferred.

In one embodiment as illustrated in FIG. 4, thephotovoltaic-panel-interfaced distillation solar-greenhouse systemincludes a solar photovoltaic panel-based distillation chamber with thewater-chamber 418 attached to and covering the transparent ceiling 405.This cools the ceiling by running cold water through the chamber overthe ceiling to enhance the condensation portion of the distillationprocess. Use of a water-cooled ceiling system also moderates the ambienttemperature within the solarhouse so that the photovoltaic panel 401functions more effectively with a more-favorable operating temperaturecondition for both solar electricity generation and waste heatutilization through co-operation of the photovoltaic panel anddistillation system together.

The embodiment of FIG. 4 also represents an example of dual-functionsolar-greenhouse system that can be used both as a photovoltaicpanel-based solarhouse system and a photobiological reactor/distillationgreenhouse by connecting the system to a CO₂ source/feeding system 419and a tail gas condensing unit 417 for saline or brine photobiologicalculture distillation liquid 404 and for making freshwater throughgreenhouse distillation while co-generating solar electricity 412. Inthis embodiment, the vapor-condensing ceiling is a transparentwater-chambered ceiling 405 that is cooled by running cold water throughthe water chamber 418 that is located over the ceiling 405. Use of thewater-cooled ceiling system 418 enhances the distillation process byincreasing the rate of vapor condensation at the inner surface of thecooled ceiling. As sunlight drives photovoltaic electricity productionwith heat generation, the vapor 413 that rises from the distillationliquid carries heat energy to the water-cooled ceiling 405 where itcondenses. Therefore, use of the water-cooled ceiling system 418 reducesthe temperature of the distillation liquid 404 and the solar panel 401that is in thermo contact with the distillation liquid to a moderatelevel, which is favorable to the performance of many solar photovoltaicpanels and in particular those that are sensitive to heat for enhancedphotovoltaic electricity generation.

Referring to FIG. 5, an embodiment of a tail-gas condensing and ventingunit 517 for use in the photovoltaic panel-based solarhouse systems ofthe present invention is illustrated. The tail-gas condensing andventing unit 517 includes a cold-water-bath chamber 523, a tail-gascondensing tube coil 524, a gas/vapor-condensate chamber 525 and avertical venting tube 526. In operation, the tail-gas condensing tubecoil 524, gas/vapor-condensate chamber 525, and vertical venting tube526 are all cooled by running cold water through the cold-water-bathchamber 523 so that the vapor in the tail gas condenses along thecondensing tube coil, which is connected with the gas/vapor-condensatechamber before venting through the vertical venting tube. Thisembodiment of the tail-gas condensing and venting unit is useful inprocessing the tail gas from a distillation greenhouse or solarhouse.When tail gas, for example, from a solarhouse or greenhouse, flowsthrough the condensing tube coil 524 that is cooled by the cold waterbath 523, its vapor condenses and flows along the condensing tube andinto the gas/vapor-condensate chamber 525 where the condensateaccumulates at the bottom of the gas/vapor-condensate chamber. Thevapor-removed tail gas is then vented through a vertical venting tube526 connected with the upper part of the tail gas-condensate chamber.The condensate, containing freshwater, is collected through use of thecondensate outlet 528 located at the bottom of the unit.

In one embodiment, for example as illustrated in FIG. 2A, the use of thephotovoltaic-panel-interfaced distillation solar-greenhouse systemproduces solar electricity 212 and, at the same time, generatesfreshwater that is collected in the freshwater collecting tank 209 andsaline/brine products from the liquid outlet 211 from seawaterintroduced through the sea water inlet 210. In operation, thedistillation source liquid, for example seawater, is initially purifiedthrough liquid sedimentation and filtration to remove any undesirablecontaminants and particles from the source liquid. A clean source liquidis introduced through an inlet into the solarhouse distillation chamber,and sunlight or solar radiation is used to drive photovoltaicelectricity and heat generation in the distillation liquid chamber. Thesolar waste heat is used to vaporize liquid molecules such as water fromthe distillation liquid, e.g., seawater. The resulting vapor iscondensed onto a tilted or arch-shaped transparent solarhouse ceiling,and the condensate, i.e., the condensed freshwater droplets, arecollected as the droplets slide along the inside surfaces of the tiltedceiling system and into condensate-collecting ducts around the wall ofthe solarhouse under the forces of surface-condensate interaction andgravity. The collected condensate, which is freshwater (distilledwater), is collected from the condensate-collecting ducts through a tubeinto a freshwater collecting/storage tank. When the solute, e.g., salt,concentration in the distillation liquid reaches a certainpre-determined high level, such as saline/brine, the saline/brineproduct is harvested through an adjustable saline/brine liquid outlet.These steps can be repeated iteratively for a plurality of operationalcycles to achieve more desirable results in terms of electrical powergeneration, freshwater generation and brine concentration. Therefore,this operational process includes the following specific process steps:a) If/when necessary, pre-purifying distillation source liquid such asseawater through liquid sedimentation and filtration to remove anyundesirable matters and particles from the source liquid; b) Introducingclean source liquid through an inlet into solarhouse distillationchamber; c) Using sunlight to drive photovoltaic electricity and heatgeneration at the distillation liquid chamber; d) Using the solar wasteheat to vaporize liquid molecules such as water from the distillationliquid; e) Condensing the vapor onto a tilted (or arch-shaped)transparent solarhouse ceiling; f) Collecting the condensate slidingalong the inside surfaces of the tilted ceiling system intocondensate-collecting ducts around the wall of the solarhouse by use ofsurface-condensate interaction and gravity; g) Transporting thecollected condensate (freshwater) from the condensate-collecting ductsthrough a tube into a freshwater collecting/storage tank; h) When solute(such as salt) concentration in the distillation liquid reaches acertain high level, harvest the saline/brine product through anadjustable saline/brine liquid outlet; and i) repeating steps a) throughh) for a plurality of operational cycles to achieve more desirableresults in terms of electrical power generation, freshwater generationand brine concentration.

In one embodiment, exemplary processes in accordance with the presentinvention use the photovoltaic-panel-interfaced distillation solarhousesystem for a plurality or series of operational cycles to achieve moredesirable results. Any one of the steps a) through i) of this processcan be adjusted or modified as desired for certain specific operationalconditions. For example, when a distillation solar-greenhouse with awater-cooled vapor-condensing ceiling system is used as illustrated, forexample, in FIG. 4, the step e) of vapor condensing can be enhanced byrunning cold water through the water-chamber ceiling system at the topof the distillation solar-greenhouse. Any one of the steps a) through i)of the process of the present invention can be applied in whole or inpart and in any adjusted combination for enhanced solar electricitygeneration and solvent distillation in accordance of this invention.

Sunlight-Concentrating Photovoltaic-Panel-Interfaced Solarhouses andRelated Systems

Referring to FIG. 6, an embodiment of a sunlight-concentratingphotovoltaic-panel-interfaced distillation solarhouse system 600 isillustrated. In this embodiment, the system comprises a sunlightfocusing lens and/or a mirror system 631, a highly heat-tolerant (HT)photovoltaic panel 601 in contact with and supported by an insulatingbase 602 and a heat-conducting transparent protective plate or film 603interfacing in between the photovoltaic-panel 601 front surface and thedistillation chamber liquid 604. The photovoltaic panel is incommunication with a pair of electrical leads 612. An arch-shapedvapor-condensing transparent ceiling 605 forms the top with liquid- andair-tight-sealing materials forming the walls of the system. A set ofcondensate-collecting ducts are located around the solarhouse wall belowthe ceiling level, and a condensate collecting tube is provided that isconnected between the condensate-collecting ducts and a condensate tank609. A source liquid inlet 610 is provided as is an adjustable liquidoutlet 611 spaced a height H7 above the photovoltaic panel 601 and asteam outlet 632 in connection with the distillation liquid chamber.

In the embodiment illustrated in FIG. 6, a large area of lenses ormirrors 631 is used to focus or to concentrate sunlight ontophotovoltaic panel 601 front surface with a relatively small area(significantly smaller than the large area of lenses or mirrors 631) sothat it will generate high power electricity and intense heat. Theintense heat can raise the temperature of a distillation liquid such aswater quickly to its boiling point, yielding hot steam and distilledwater. In addition, the photovoltaic semiconductor properties allowsolar cells to operate more efficiently in concentrated light as long asthe photovoltaic cell junction temperature is kept cool by a suitableheat sink such as the distillation liquid. Consequently, increasing thesunlight concentration ratio, for example from about 2 to about 20 suns,improves the performance of high efficiency photovoltaic cells.

In one embodiment, the sunlight collecting/focusing lens and/or mirrorsystem collects and concentrates sunlight onto the heat-tolerant (HT)photovoltaic panel in the distillation chamber to generate electricityand intense heat, for example above 100° C. Due to the use of thesunlight focusing lens/mirror system that can collect and concentratesunlight onto the photovoltaic panel front surface, the concentratedsunlight intensity on the photovoltaic panel (FIG. 6) is much higherthan that without using a sunlight concentrating lens system (FIG. 2).Consequently, the temperature of the sunlight-focusing photovoltaicpanel-interfaced distillation chamber (FIG. 6) can be significantlyhigher than that of embodiments without a sunlight focusing lens/mirrorsystem. For example, when a sunlight focusing lens/mirror system thatconcentrates sunlight intensity between about 2 and about 20 suns isused, the distillation liquid water can reach its boiling temperature(100° C.) within about 5-30 minutes, depending on the geographiclocation and weather conditions. Certain sunlight collecting/focusinglens and/or mirror system as powerful as 1000 suns are now commerciallyavailable. Use of such powerful sunlight collecting/focusing systemsgenerates high power electricity and very intense heat. To suit with thehigher-temperature (>100° C.) operation, high-temperature-tolerantphotovoltaic panels and structural materials are used in theconstruction of sunlight-concentrating photovoltaic-panel-interfaceddistillation solarhouse system that use a sunlight-focusing lens/mirrorsystem that collects and concentrates more than 1.5 suns. Therefore, thesunlight-concentrating photovoltaic panel-interfaced distillationchamber system of FIG. 6 can be used to produce boiled water, hot steamand distilled water while co-generating photovoltaic electricity.

In one embodiment, the higher-temperature sunlight-concentratingphotovoltaic panel-interfaced distillation chamber system, for example,of FIG. 6, is used in combination with other embodiments of the solardistillation systems of the present invention for example in a seriesarrangement. Referring to FIG. 7, an embodiment of a series of solardistillation systems 700 where the system of FIG. 6 is the second systemin the series is illustrated. As illustrated, the higher-temperature(>100° C.) sunlight-concentrating photovoltaic panel-interfaceddistillation system is used in combination with a freshwater-makingphotovoltaic panel distillation system. As illustrated, thefreshwater-making photovoltaic panel distillation system embodiment ofFIG. 2 is used as the first system in the series; however, anyembodiment of a fresh-water making system in accordance with the presentinvention can be used. Freshwater (condensate) made from seawaterthrough the lower-temperature, e.g., <100° C., typically in a range ofabout 4° C. to about 70° C., photovoltaic panel-based distillationsolarhouse system is passed through a condensate tube 708 that isconnected as the source liquid feedstock for the higher-temperature(>100° C.) sunlight-concentrating photovoltaic panel-interfaceddistillation system. The higher-temperature system in the series is usedto make boiled water, hot steam, and distilled water while co-generatinghigh power photovoltaic electricity. Hot steam can be employed for anumber of applications including sterilization for photobiologicalculture media and reactors.

According to another embodiment, a photovoltaic-panel-interfaceddistillation solarhouse can be flexibly modified to serve otherfunctions such as producing hot water and solar electricity. Referringto FIG. 8A, an exemplary embodiment of a modifiedphotovoltaic-panel-interfaced solarhouse 800 is illustrated that is usedto produce hot liquid such as hot water while co-generating solarelectricity. This modified photovoltaic-panel-interfaced solarhousesystem includes a back-insulated heat-tolerant photovoltaic panel 801mounted on an insulating support base 802 and a flexible heat-conductingtransparent protective plate or film 803 interfacing in between thephotovoltaic-panel 801 front (top) surface and the water (or antifreeze)liquid chamber 804. A flexible heat-insulating transparent plate or film833 is provided in between the water (or antifreeze) liquid chamber 804and the heat-insulating air chamber 834 to separate the two chambers ofthe system. An arch-shaped heat-insulating transparent ceiling 805, forexample, a clear transparent plastic cover, is provided as the top thatis supported by heat-insulating liquid-tight and air-tight-sealingmaterials, such as transparent plastic films as the walls 806. The water(or antifreeze) liquid chamber 804 is formed by the heat-conductingtransparent protective plate or film 803 as its bottom, part of theheat-insulating liquid-tight and air-tight-sealing walls 806 as itswalls, and the heat-insulating transparent plate or film 833 as its topcover. Whereas, the heat-insulating transparent plate or film 833 andthe arch-shaped heat-insulating transparent ceiling 805 together formthe heat-insulating air chamber 834 that is located above the water (orantifreeze) liquid chamber 804. The system also includes a source liquidpump/inlet 810, an adjustable hot liquid outlet 811 in connection withthe liquid chamber 804 and spaced a height H8 above the photovoltaicpanel and a set of electricity output connectors 812. The hot liquidoutlet 811 extended from the water (or antifreeze) liquid chamber 804 isadjustable through the height H8 above the photovoltaic panel.

In one preferred embodiment, heat-insulating, as opposed toheat-conducting, transparent materials such as heat-insulatingtransparent plastics are used in the construction of the ceiling andwalls for the hot water-making photovoltaic-panel-interfaced solarhouseembodiment of FIG. 8A. This is in contrast to other embodiments of thephotovoltaic-panel-interfaced distillation solarhouse illustrated inFIGS. 1-4 where the solar-greenhouse ceiling is made preferably fromcertain heat-conducting transparent plastics to serve as avapor-condensing surface for the purpose of facilitating a distillationapplication. As shown in FIG. 8A, there is a heat-insulating air chamber834 located above the water (or antifreeze) liquid chamber 804 toprovide more-effective heat-insulation for the modified solarhouse. Inoperation, when sunlight passes through both the heat-insulating airchamber 834 and the water (or antifreeze) liquid chamber 804 and drivesphotovoltaic electricity generation, it co-produces heat at thephotovoltaic panel. The solar heat co-produced from the photovoltaicpanel is transferred through a nearly one-dimensional heatconduction/flow across the heat-conducting transparent film (plate) 803into the water (or antifreeze) liquid 804 above the photovoltaic panel801 to produce hot liquid such as hot water, which may be valuable forboth residential and industrial applications.

This modified photovoltaic-panel-interfaced solarhouse (FIG. 8A) canalso be applied in combination with a sunlight focusing lens and/ormirror systems, e.g., FIG. 6 at 631, to further enhance the capabilityof producing hot water while co-generating solar electricity 812.

As shown in FIG. 8B, another exemplary embodiment of a modifiedphotovoltaic-panel-interfaced solarhouse 1800 is illustrated that isused to produce hot liquid coolant such as hot water or hot antifreezeliquid while co-generating solar electricity. Hot water or hotantifreeze liquid can be used to provide heating for homes and otherapplications. This modified photovoltaic-panel-interfaced solarhousesystem includes a heat-tolerant photovoltaic panel 1801 mounted on topof a water or antifreeze liquid chamber 1804 that is constructed withpart of the solarhouse chamber wall in between an insulating supportbase 1802 and a flexible heat-conducting plate or film 1803 interfacingwith the photovoltaic-panel 1801 back (bottom) surface. That is, thewater (or antifreeze) liquid chamber 1804 is formed by theheat-conducting plate or film 1803 as its top, part of theheat-insulating liquid-tight and air-tight-sealing walls 1806 as itswalls, and the heat-insulating base support material 1802 as its bottom.A flexible heat-insulating transparent plate or film 1833 is provided inbetween the top surface of the solar photovoltaic panel 1801 and theheat-insulating air chamber 1834 to help retain the solar heat. Anarch-shaped heat-insulating transparent ceiling 1805, for example, aclear transparent plastic cover, is provided as the top that issupported by heat-insulating liquid-tight and air-tight-sealingmaterials, such as transparent plastic films as the walls 1806. Whereas,the heat-insulating transparent plate or film 1833 and the arch-shapedheat-insulating transparent ceiling 1805 together form theheat-insulating air chamber 1834 that is located above the solar panel1801. The system also includes a source liquid pump/inlet 1810, anadjustable liquid outlet 1811 in communication with the liquid chamber1804. This modified photovoltaic-panel-interfaced solarhouse 1800 canutilize solar waste heat to generate hot liquid while co-producing solarphotovoltaic electricity. The use of antifreeze liquid in this systemenables application of the technology in all seasons including freezingweather or cold geographic locations.

A further exemplary embodiment of a modifiedphotovoltaic-panel-interfaced solarhouse 2800 is illustrated in FIG. 8C,which is used to produce hot liquid coolant such as hot water or hotantifreeze liquid while co-generating solar electricity. This modifiedphotovoltaic-panel-interfaced solarhouse system has two liquid chambers:one (chamber 2804) located above solar panel 2801 and the other (chamber1804) located below solar panel 2801. Briefly, this solarhouse systemcomprises: 1) A heat-tolerant photovoltaic panel 2801 mounted on top ofa water (or antifreeze) liquid chamber 1804 that is constructed on aninsulating support base 1802 as its bottom, using part of solarhousewall 2806 as its walls and a flexible heat-conducting plate or film 1803as its top interfacing with the photovoltaic-panel 1801 back (bottom)surface; 2) A heat-insulating transparent plate or film 2833 is providedin between the heat-insulating air chamber 2834 and the liquid chamber2804 located above the top surface of solar photovoltaic panel 2801; 3)An arch-shaped heat-insulating transparent ceiling 2805, for example, aclear transparent plastic cover, is provided as the top that issupported by heat-insulating liquid-tight and air-tight-sealingmaterials, such as transparent plastic films as the walls 2806; 4) Thewater (or antifreeze) liquid chamber 2804 above solar panel 2801 isformed by the heat-conducting transparent plate or film 2803 as its top,part of the heat-insulating liquid-tight and air-tight-sealing walls2806 as its walls, and the heat-conducting transparent plate/film 2803as its bottom; 5) The heat-insulating transparent plate or film 2833 andthe arch-shaped heat-insulating transparent ceiling 2805 together formthe heat-insulating air chamber 2834 that is located on top of theliquid chamber 2804 above solar panel 1801; 6) The system also includesa source liquid pump/inlet 2810, an adjustable liquid outlet 2811 incommunication with liquid chamber 1804, a liquid inlet 2820 and a liquidout 2821 in coordination with liquid chamber 2804, and a set ofelectricity output connectors 2812. The use of the two liquid chambers2804 and 1804 enables more effective utilization of solar waste heat,co-beneficial to the performance of solar photovoltaic panel 2801.

Yet another exemplary embodiment of a modifiedphotovoltaic-panel-interfaced solarhouse 3800 is illustrated in FIG. 8D,which is used to produce hot liquid coolant such as hot water or hotantifreeze liquid while co-generating solar electricity. This modifiedphotovoltaic-panel-interfaced solarhouse system comprises: 1) Aheat-tolerant photovoltaic panel 3801 mounted on top of a water (orantifreeze) liquid chamber 3804; 2) Water (or antifreeze) liquid chamber3804 below solar panel 3801 is formed by the heat-insulating basesupport material 3802 as its bottom, part of the heat-insulatingliquid-tight and air-tight-sealing walls 3806 as its walls, and theheat-conducting plate or film 3803 as its top interfacing with thephotovoltaic-panel 3801 back (bottom) surface; 3) A flexibleheat-insulating transparent plate or film 3833 covers the top surface ofsolar panel 3801 to help retain solar heat; and 4) The system alsoincludes a source liquid pump/inlet 3810, an adjustable hot liquidoutlet 3811 passing through the wall of liquid chamber 3804, and a setof electricity output connectors 3812 in communication with solar panel3801.

According to one of various embodiments, a coolant is selected for usefrom the group consisting of water, antifreeze liquid, polyalkyleneglycol, oils, mineral oils, silicone oils such as polydimethylsiloxane,fluorocarbon oils, transformer (insulating) oil, refrigerants, andcombination thereof.

FIG. 8E illustrates another exemplary embodiment 6800 that is aninnovative use of solarhouse 3800 model with a self-circulating coolantfluid for heat exchange with a distillation house to make distillationproducts such as seawater (distilled water) while co-generatingelectricity. As shown in FIG. 8E, the coolant-coupled photovoltaicsolar-greenhouse distillation system 6800 comprises two majorcomponents: (1) a coolant circulating photovoltaic solarhouse systemthat generates hot coolant while co-generating electricity with a set ofelectricity output connectors 6812 in communication with solar panel6801; and (2) a coolant-coupled distillation chamber system thatgenerates distillation products such as freshwater by using the heatthrough heat-exchange with the hot coolant from the liquid coolantchamber 6804 of the photovoltaic solarhouse system. Specifically, thecoolant circulating photovoltaic-panel-interfaced solarhouse system(major component 1) comprises: 1) Photovoltaic panel 6801 mounted on topof a liquid coolant (such as water or antifreeze) chamber 6804 connectedwith a liquid coolant circulating tube 6849 and a coolant outlet/valve6841; 2) Liquid coolant chamber 6804 below solar panel 3801 is formed bythe heat-insulating base support material 6802 as its bottom, part ofthe heat-insulating liquid-tight and air-tight-sealing walls as itswalls, and the heat-conducting plate or film 6803 as its top interfacingwith the photovoltaic-panel 6801 back (bottom) surface; and 3)Anti-reflection and heat-insulating transparent plate or film 6833covers the top surface of solar panel 6801 to help retain solar heat.Meanwhile, the coolant-coupled distillation chamber system (majorcomponent 2) comprises: 4) Coolant chamber 6844 comprising an insulatedbase 6842 as its bottom and a heat-conducting plate (or film) 6843 asits top is connected with the liquid coolant chamber 6804 of thephotovoltaic solarhouse system through a hot liquid coolant tube 6848and a liquid coolant circulating tube 6849; 5) Distillation chambersystem comprising distillation house ceiling 6865 as its top/walls and aheat-conducting plate (or film) 6843 as its bottom in heat exchange withthe coolant chamber 6844; and 6) The system also includes a seawaterinlet 6860 connected with the distillation chamber containingdistillation liquid 6854 and vapor 6863, condensate droplet 6864,condensate collecting duct 6867, and condensate collecting tube 6868leading to freshwater collecting tank 6869.

In this exemplary embodiment 6800 (FIG. 8E), the solar panel waste heatis taken by heat-exchanging coolant, such as water or an antifreezeliquid at the back of the solar panel, which is preferably placed at atilted angle (so that its upper end is significantly higher than itsother end) to face the sun. As the coolant liquid heats up, its volumeexpands so that the heated liquid will flow up toward the outlet/valve6841 at the solar-panel liquid chamber's upper end that is connected toa distillation house's coolant chamber 6844 through an insulatedhot-liquid-coolant tube 6848. After the hot coolant flows into thedistillation house's coolant chamber, it is cooled here by heat exchangethrough a heat-conducting plate (or film) 6843 with a distillationchamber liquid 6854 (such as seawater) where the heat is utilized tovaporize its seawater for distillation to make freshwater. On the otherhand, when the coolant liquid is cooled, its liquid density increases sothat it will flow from the distillation house's coolant chamber 6844through a circulating coolant tube 6849 into the lower end of thesolar-panel liquid chamber 6804. The combined effects of the rising hotcoolant liquid flow toward the upper end of the solar-panel liquidchamber and the cooled coolant liquid flows from the distillationhouse's coolant chamber into the lower end of the solar-panel liquidchamber result in a self-sustained circulating coolant flow through thesystem (without an external pump) to provide beneficial cooling to thesolar panel for solar electricity generation while utilizing the wasteheat at the distillation house to make freshwater.

As shown in FIG. 8E, the distillation house with its ceiling 6865 inthis system operates in a shade behind (or below) the solar panel 6801.In this way, the solar panels can fully use their sunlight collectionarea with no shading by any of their associated distillation-houseceilings in a given Earth surface area. Therefore, the ceiling surfacesunlight reflection loss associated with the systems of FIGS. 1-2E and3-8C is eliminated in this system design (FIG. 8E).

Table 1 presents an example of an estimatedsolar-to-electricity-and-useful-heat-product energy conversionefficiency for this circulating-coolant-coupled model design (FIG. 8E)in comparison with a ceiling-top associated distillation system (FIG.2A) and a membrane-distillation system (FIG. 2F) that both utilize thewaste heat immediately by distillation. Assuming a 0.5% rise inphotovoltaic efficiency for every degree (° C.) of cooling, a cooling byabout 30° C. by solvent distillation or by passing a coolant liquidthrough the chamber underneath a solar panel would result in aphotovoltaic efficiency improvement by 15%. Assuming waste-heatutilization efficiency of about 60% for the immediate heat-utilizationdistillation systems (FIGS. 2A and 2F) and 50% for thecirculating-coolant-coupled-distillation design (FIG. 8E) respectively,the solar-to-electricity-and-useful-heat-product total energy conversionefficiency was estimated to be about 60-66% for these systems (Table 1).They are all about 4 times better than today's photovoltaic panel usedalone without an interfaced solvent distillation system.

TABLE 1 Example of estimated solar-to-electricity-and-useful-heat-product energy conversion efficiencies of photovoltaicsolar-greenhouse distillation systems. Coolant- Ceiling Top Membrane-Coupled Distillation Distillation Distillation System System System(FIG. 2A) (FIG. 2F) (FIG. 8E) Ceiling surface sunlight −15% 0 0reflection loss factor (Robertson et al 2011, DOI 10.1007/s11120-011-9631-7) Photovoltaic +15% +15% +15% improvement factor owing tocooling effect* Solar-to-electricity  15%  15%  17% energy conversionefficiency** Improvement of process +43% +51% +43% energy efficiencyowing to waste-heat utilization*** Solar-to-electricity-and-  58%  66% 60% useful-heat-product total energy conversion efficiency Solarelectricity 0.72 kWh 0.816 kWh 0.816 kWh generation*** per m² per m² perm² per day per day per day Freshwater 3.06 L per 3.63 L per 2.93 L perproduction*** m² per day m² per day m² per day *Assuming a cooling byabout 30° C. and a 0.5% rise in PV efficiency for every degree (° C.) ofcooling; **Assuming use of a photovoltaic panel with asolar-to-electricity energy conversion efficiency of 15% and theremainder 85% goes to heat; ***Assuming average solar radiation energyof 200 watts per day per square meter of horizontal surface, andwaste-heat utilization efficiency about 60% for the immediateheat-utilizing distillation systems (FIGS. 2A and 2F) and 50% for thehot-coolant-making and then-hot-coolant-circulation-coupled distillationdesign (FIG. 8E), respectively.

FIG. 8F illustrates another exemplary embodiment 7800 of a photovoltaicpanel-interfaced hydrophobic microporous plate distillation systemcoupled through a self-sustained circulating coolant fluid for heatexchange to make freshwater by distillation while co-generating solarelectricity; As shown in FIG. 8F, the photovoltaic panel-interfacedhydrophobic microporous plate membrane distillation system 7800comprises two major components: (1) a coolant circulating photovoltaicpanel-interfaced hydrophobic microporous plate membrane distillationsystem that generates hot liquid condensate as the hot coolant outputwhile co-generating electricity with a set of electricity outputconnectors 7812 in communication with solar panel 7801; and (2) acoolant-coupled distillation chamber system that generates distillationproducts such as freshwater by using the heat through heat-exchange withthe hot coolant flow from the condensation liquid chamber 7809 of thephotovoltaic panel-interfaced membrane distillation system throughconnection of hot coolant outlet 7841 and hot liquid coolant tube 7848.Specifically, the coolant circulating photovoltaic-panel-interfacedhydrophobic microporous plate distillation system (major component 1)comprises: 1) Photovoltaic panel 7801 mounted on top of a liquid feedchamber 7804 that is formed with a hydrophobic microporous platemembrane 7870 as its bottom, part of the heat-insulating liquid-tightand air-tight-sealing walls as its walls, and a heat-conducting plate orfilm 7803 as its top interfacing with the photovoltaic-panel 7801 back(bottom) surface; 2) Condensation liquid chamber 7809 that is formedbelow the liquid feed chamber 7804 by hydrophobic microporous platemembrane 7870 as its top, part of the heat-insulating liquid-tight andair-tight-sealing solarhouse walls as its side walls, and theheat-insulating base plate 7806 as its bottom; 3) hot coolant outlet7841 and liquid coolant circulating tube 7849 connected respectivelywith the upper and bottom ends of the condensation liquid chamber 7809;4) Source liquid inlet 7811 and liquid outlet 7810 connectedrespectively with the upper and bottom ends of liquid feed chamber 7804;5) Anti-reflection and heat-insulating transparent plate or film 7833covers the top surface of solar panel 7801 to help retain solar heat.Meanwhile, the coolant-coupled distillation chamber system (majorcomponent 2) comprises: 6) Coolant chamber 7844 comprising an insulatedbase 7842 as its bottom and a heat-conducting plate (or film) 7843 asits top, which is connected with the condensation liquid chamber 7809 ofphotovoltaic-interfaced membrane distillation system through a hotliquid coolant tube 7848 and a liquid coolant circulating tube 7849; 7)Distillation chamber system comprising distillation house ceiling 7865as its top/walls and a heat-conducting plate (or film) 7843 as itsbottom in heat exchange with the coolant chamber 7844; 8) Condensatecollecting tank 7872 that has a condensate tube outlet 7871 connectedwith the liquid coolant circulating tube 7849; and 9) The system alsoincludes a seawater inlet 7860 connected with the distillation chambercontaining distillation liquid 7854 and vapor 7863, condensate droplet7864, condensate collecting duct 7867, and condensate collecting tube7868 leading to freshwater collecting tank 7869.

This system 7800 (FIG. 8F) is similar to that of 6800 (FIG. 8E) exceptthat the system 7800 employs a membrane distillation process acrosshydrophobic microporous plate 7870 in between the solar panel-interfacedliquid feed chamber 7804 and the condensation liquid chamber 7809. Thephotovoltaic panel 7801 in this system can be placed with its frontsurface facing the sun using any desirable angle from the horizontalearth surface. Saline water feed in chamber 7804 is heated (by the wasteheat from solar panel 7801) to increase its vapor pressure, whichgenerates the difference in partial pressure between the two sides ofhydrophobic microporous plate membrane 7870. Hot water evaporatesthrough nonwetted pores of the hydrophobic microporous plate membrane7870, which cannot be wetted by the aqueous solution in contact with andonly vapor and noncondensable gases should be present within themembrane pores. The passed vapor is then condensed at the bottom side ofhydrophobic microporous plate membrane 7870 directly into the coolercondensate liquid in the condensation liquid chamber 7809 to producedistilled water as shown in FIG. 8F. Note, typically, there is no airgap between the hydrophobic microporous plate membrane 7870 bottomsurface and the cooler liquid condensate in the condensation liquidchamber 7809. Therefore, this process represents a type of directcontact hydrophobic microporous plate membrane distillation. As thecooled liquid condensate from the distillation house's coolant chamber7844 flows as a coolant liquid through the circulating tube 7849 intothe lower end of the condensation liquid chamber 7809, it gradually getshotter there by the hydrophobic microporous plate membrane distillationprocess so that it flows toward the upper end of the condensation liquidchamber 7809, which drives a self-sustained circulating coolant flowthrough the system (without an external pump) to provide beneficialcooling to the photovoltaic panel 7801 for solar electricity generationwhile utilizing the waste heat at the distillation house to vaporizedistillation chamber liquid 7854 to make freshwater. The distilled waterproduct from the hydrophobic microporous plate membrane distillationprocess is collected into the condensate collecting tank 7872 that has acondensate outlet tube connected with liquid coolant circulating tube7849. It is a preferred practice to keep the condensate tube outlet 7871immersed under the condensate liquid level 7873 in the condensatecollecting tank 7872 so that it can automatically collect the distilledwater product through liquid coolant circulating tube 7849 withoutintroducing air bubbles into the liquid coolant circulating tube 7849 inconnection with the condensation liquid chamber 7809 and theheat-exchanging liquid chamber 7844.

FIG. 8G illustrates another exemplary embodiment 8800 of a photovoltaicpanel-interfaced hydrophobic microporous plate membrane distillationsystem comprises: 1) Photovoltaic panel 8801 mounted on the top of aliquid feed chamber 8804 that is formed below solar panel 8801 with ahydrophobic microporous plate membrane 8870 as its bottom, part of theheat-insulating liquid-tight and air-tight-sealing solarhouse walls asits side walls, and a heat-conducting plate or film 8803 as its topinterfacing with the photovoltaic-panel 8801 back (bottom) surface; 2)Condensation chamber 8809 formed by the hydrophobic microporous platemembrane 8870 as its top, part of the heat-insulating liquid-tight andair-tight-sealing solarhouse walls as its side walls, and theheat-conducting base plate 8806 as its bottom; 3) Anti-reflection andheat-insulating transparent plate or film 8833 covering the top surfaceof solar panel 8801 to help retain solar heat; 4) Source liquid inlet8811 and liquid outlet 8810 connected respectively with the upper andbottom ends of the liquid feed chamber 8804; 5) Height-adjustablecondensate collecting tube 8849 and a flexible outlet 8841 connectedrespectively with the bottom and upper ends of the condensation chamber8809; and 6) Condensate collecting tank 8872 that has a condensate tubeoutlet 8871 connected with the height-adjustable condensate collectingtube 8849.

This system 8800 (FIG. 8G) is similar to that of 7800 (FIG. 8F) exceptthat the system 8800 employs an enhanced condensation chamber 8809comprising a heating-conducting base plate 8806 and using aheight-adjustable condensate collecting tube 8849 to control the ratioof the direct contact membrane distillation to the air gap membranedistillation. For best result, it is a preferred practice to place thephotovoltaic panel 8801 front surface facing the sun with a proper angleabove the horizontal earth surface. This angle is selected from thegroup consisting of 15°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 85°, and/orwithin a range bounded by any two of these values. In this way, theheat-conduction base plate 8806 of the condensation chamber 8809 can beeffectively cooled by a natural air convection flow under thecondensation chamber 8809 along the heat-conduction base plate 8806 backsurface. In operation, the condensate liquid level 8873 is controlled byadjusting the vertical distance H8274 from the upper end of condensationchamber 8809 to the highest point of the height-adjustable condensatecollecting tube 8849, which is used as a setting level 8275 for thecondensate liquid level 8876 by using the height-adjustable condensatecollecting tube 8849. When the condensate liquid level 8876 in thecondensation chamber 8809 exceeds the set level 8275, the condensateliquid flows out of the condensation chamber 8809 and passes through thehighest point of the height-adjustable condensate collecting tube 8849and condensate tube outlet 8871 into the condensate collecting tank 8872until the condensate liquid level 8876 equals to the set liquid level8725. For example, when the height-adjustable condensate collecting tube8849 is raised all the way up to the point at the upper end ofcondensation chamber 8809, the vertical distance H8274 between thecondensation chamber 8809 upper end and the condensate liquid level 8876will be zero so that the condensate liquid will occupy the entire volumeof the condensation chamber 8809; under this condition, the photovoltaicpanel-interfaced hydrophobic microporous plate distillation process is100% in the mode of direct contact membrane distillation. On the otherhand, when the height-adjustable condensate collecting tube 8849 islowered all the way down and the vertical distance H8274 equals to thevertical height of the entire condensation chamber 8809 so that nocondensate liquid will occupy the condensation chamber 8809; in thiscase, the photovoltaic panel-interfaced hydrophobic microporous platemembrane distillation system operates with 100% air gap membranedistillation. When the condensate liquid level 8876 is adjusted to amiddle level, the photovoltaic panel-interfaced hydrophobic microporousplate membrane distillation system will operate with a mixed mode incombination of direct contact membrane distillation with air gapmembrane distillation. These two modes of membrane distillation requiresomewhat different membrane properties to achieve their bestperformances. For an example, the direct contact membrane distillationrequires a hydrophobic microporous plate membrane that has low heatconductivity; otherwise would result in high heat energy loss to thecondensation chamber because of the liquid-membrane-liquid heatconduction from the hot liquid feed 8804 through plate membrane 8870directly to the cooled condensate liquid in the condensation chamber8809. On the other hand, the air gap membrane distillation process isnot too sensitive to the membrane heat conductivity; a hydrophobicmicroporous plate membrane that has relatively high heat conductivitycan be employed since the air gap between the hydrophobic microporousplate membrane 8870 and the heat-conducting base plate 8806 innersurface can help limit the heat conduction energy loss. Therefore, theinnovative method taught here in using a height-adjustable condensatecollecting tube 8849 to control the ratio of direct contact membranedistillation vs. air gap membrane distillation enables the use ofvarious hydrophobic membranes to achieve their best possibleperformances with a desired ratio between the two membrane-distillationmodes. The product water can be harvested by use of condensatecollecting tank 8872 that has a condensate tube outlet 8871 connectedwith the upper end of height-adjustable condensate collecting tube 8849.It is a preferred practice to keep the condensate tube outlet 8871immersed under the condensate liquid level 8873 in the condensatecollecting tank 8872 so that it can automatically collect the productwater without introducing any air bubbles into the height-adjustablecondensate collecting tube 8849.

According to one of the various embodiments, the source feed liquid forphotovoltaic panel-interfaced distillation systems with and without ahydrophobic microporous membrane distillation process is selected fromthe group consisting of seawater, brackish water, saline water, brineliquid, surface water, ground water, well-water, non-potable water,photobiological liquid culture media, beer, methanol solutions, ethanolsolutions, propanol solutions, 1-hydroxy-2-propanone solutions,butanol/isobutanol solutions, cyclohexanol solutions, tert-amyl alcohol,pentanol solutions, hexadecan-1-ol solutions, polyhydric alcoholssolutions, primary alcohol solutions, higher alcohols solutions,aldehyde solutions, aldehyde hydrate solutions, carboxylic acidssolutions, lactose solutions, biomass-derived hydrolysate solutions,glucose solutions, fructose solutions, sucrose solutions, furanosesolutions, pyranose solutions, monosaccharides solutions,oligosaccharides solutions, polysaccharides solutions, acetic acidsolutions, propionic acid solutions, citric acid solutions, lactic acidsolutions, acetone solutions, other organic solutions and/or solventsand combinations thereof.

According to one of the various embodiments, any number of variousphotovoltaic panel-interfaced distillation systems with and without ahydrophobic microporous membrane distillation process are used inseries, in parallel, and/or in combination with certainsunlight-concentrating mechanism comprising sunlight focusing lensand/or mirror systems, and with photobioreactors/greenhouse distillationsystems to achieve more desirable results in desalination and harvestingof advanced biofuels and bioproducts such as ethanol while co-generatingsolar electricity.

Application of Photovoltaic Panel-Interfaced Distillation System forSalt Making

According to one of the exemplary embodiments of the photovoltaicpanel-interfaced distillation solarhouse system in accordance with thepresent invention, the system is used to make salt from seawater and/orbrine and to produce electricity and freshwater. Therefore, sea salt canbe generated from seawater while generating photovoltaic electricity(FIG. 3). Since the photovoltaic panel-interfaced distillation processis operated in a sealed solarhouse chamber, the distillation liquid isprotected from rain, dusts, insects, bird droppings and otherundesirable environmental elements or contaminates from which aconventional open pond/pan salt farm may suffer. Therefore, use of aphotovoltaic panel-interfaced distillation solarhouse more reliablyproduces clean and quality sea salt products when compared to aconventional open pond/pan salt farm. Unlike the conventional openpond/pan salt farms that generally require a relatively dry season (anyunseasonal rains could ruin their salt farm harvest), use of thephotovoltaic-panel-interfaced distillation solarhouse systems of thepresent invention, e.g., FIG. 3, enables the making of quality sea saltseven in the rainy season or in a rainy geographic regions, since thesolarhouse distillation chamber system is sealed and can prevent rainsfrom entering into the distillation liquid. Therefore, exemplaryembodiments in accordance with the present invention also represent arain-proof and dust-proof sea salt-making technology that can bedeployed throughout the world and that enables utilization of brineinstead of brine discharge into the environment.

As the rain-proof/dust-proof salt-making distillation process of thepresent invention progresses while co-generating solar electricity, thesalt concentration in the distillation seawater/brine liquid graduallyreaches about 35%. At these concentrations, salt crystallization willoccur initially as flakes that typically settle down to the bottom ofthe distillation chamber. Referring to FIG. 3, this salt making processis enhanced by feeding or blowing dry air into the distillationsolarhouse chamber that is preferably equipped with a dry air pump 316and a tail gas condensing/vent system 317. As dry air is introduced andflows through the brine liquid distillation 304 chamber, it acceleratesevaporation by carrying the vapor from distillation brine liquid to thetail gas condensing/vent system, an embodiment of which is illustratedin FIG. 5, where water vapor is condensed to produce freshwater beforeair venting. The acceleration of water evaporation from distillationbrine liquid enhances salt crystallization in the brine. The sea saltproducts can then be readily harvested from the salt-making distillationchamber. With a foldable plastic distillation solarhouse, the sea saltproduct can be harvested by rolling up the foldable plastic distillationchamber from one end to the other end with minimal cost.

According to one of the embodiments in accordance with the presentinvention, for example as illustrated in FIG. 3, therain-proof/dust-proof salt-making operational process includesintroducing clean seawater through an inlet into the solarhousedistillation chamber. Sunlight is used to drive both photovoltaic-panelelectricity and heat generation at the distillation liquid chamber, andthe solar waste heat is used to vaporize water from the distillationliquid. The vapor is condensed onto a tilted or arch-shaped transparentsolarhouse ceiling, and the condensate, i.e., freshwater droplets, iscollected with a set of condensate-collecting ducts around thesolarhouse wall under the forces of surface-condensate interaction andgravity. The collected condensate, i.e., freshwater, is collected into afreshwater collecting/storage tank. Salt making and crystallization isenhanced by blowing dry air through the distillation brine/salt makingchamber to the tail gas condensing/vent system, and the salt/brineproducts are harvested from the distillation brine/salt making chamber.The steps of this process are repeated iteratively for a plurality ofoperational cycles to achieve the desired products and results. Thisoperational process includes the following specific process steps: a)Introducing clean seawater through an inlet into the solarhousedistillation chamber; b) Using sunlight to drive both photovoltaic-panelelectricity and heat generation at the distillation liquid chamber; c)Using the solar waste heat to vaporize water from the distillationliquid; d) Condensing the vapor onto a tilted (or arch-shaped)transparent solarhouse ceiling; e) Collecting the condensate with a setof condensate-collecting ducts around the solarhouse wall by use ofsurface-condensate interaction and gravity; f) Transporting thecollected condensate (freshwater) into a freshwater collecting/storagetank; g) Enhancing salt making/crystallization by blowing dry airthrough the distillation brine/salt making chamber to the tail gascondensing/vent system; h) Harvesting the salt/brine products from thedistillation brine/salt making chamber; and i) repeating steps a)through h) for a plurality of operational cycles to achieve moredesirable results.

The above process to use the photovoltaic-panel-interfaced distillationsolarhouse system can be repeated for a plurality of operational cyclesto achieve more desirable results. Any of the steps the steps a) throughi) of this process described above can also be adjusted in accordance ofthe present invention to suit for certain specific conditions. Forexample, when a foldable plastic distillation brine/salt-making chamberis used as illustrated in FIG. 3, the step h) of salt/brine productsharvesting can be accomplished by folding up the foldable plasticdistillation brine/salt-making chamber from one end to the other withminimal cost. In practice, any of the steps a) through i) of the processcan be applied in full or in part, and/or in any adjusted combinationfor enhanced salt and freshwater production from seawater whilegenerating photovoltaic electricity in accordance of this invention.

Application of Solar Panel Distillation System for Screening of BrineSalinity Tolerant Photosynthetic Organisms

In a conventional seawater desalination process such as multi-stageflash distillation or reverse osmosis, the resulting brine liquid isoften discharged into the environment, which is a serious environmentalconcern. Reverse osmosis, for instance, may require the disposal ofbrine with salinity twice that of normal seawater. The benthic communitycannot accommodate such an extreme change in salinity and manyfilter-feeding animals are destroyed by osmotic pressure when such brinewater is returned to the ocean. Furthermore, the brine discharging flowsare considerably large, generally up to 40% (for membrane basedtechnologies, like reverse osmosis) and up to 90% (for thermaltechnologies, like multi-stage-flash, including cooling water) of theseawater intake flow rate. Therefore, any technology that could utilizelarge amounts of brine in a beneficial manner (instead of dischargingthe brine to the environment) would be helpful. The present inventioncan help address this issue as well, since it also teaches how toproductively utilize the brine product as an algal culture medium forphotobiological liquid mass culture, in addition to therain-proof/dust-proof brine-to-salt making process described above witha photovoltaic panel-interfaced distillation solarhouse system.

Establishing the capability of using brine as a mass photobiologicalliquid culture medium is of primary importance since photobiological(such as algal) mass culture can potentially use large amounts of brineliquid for photosynthetic production of advanced biofuels andbioproducts. In order to establish such a capability to productivelyutilize brine liquid that contains more than 5% of salt, it is essentialto develop certain special (and often rare) high-salinity tolerantspecies and/or strains of algae or blue-green algae (oxyphotobacteriaincluding cyanobacteria and oxychlorobacteria). According to one of thevarious embodiments, the photovoltaic panel-interfaced distillationsolar-greenhouse system and its associated saline/brine products can beused also to help develop, screen, and culture certain specialphotosynthetic organisms that are highly tolerant to salinity. Salinityis often associated with alkalinity. Therefore, it is a preferredpractice to develop and screen for alkaliphilic (high pH tolerant) andhalophilic (high salt tolerant) types of oxygenic photosyntheticstrains.

According to one of the various embodiments, application of saline/brineproducts in development and screening (select) for highlysalinity-tolerant photosynthetic organisms such as highly salt-tolerantalgae or cyanobacteria will not only enable the use of saline/brine as aphotobiological liquid culture medium, but also provide a significantapproach in helping achieve species control for certain photobiologicalmass cultures. For example, in the conventional algal mass culture forproduction of advanced biofuels and/or bioproducts, an effectivetechnique to achieve species control is often highly desirable to growand maintain a relatively pure mass culture. A common challenge in manyalgal mass culture applications is that when the culture is growing,certain organic materials (such as acetate and/or ethanol) released fromcertain algal cells into the liquid medium could enable the growth ofother undesirable microorganisms such as oxidative bacteria(heterotrophs) which can often mess up the algal culture. According toone of the various embodiments, this technical challenge could beovercome by using high-salinity brine (with salinity above 5% salt) as aliquid culture medium for certain special (rare) high-salinity tolerantphotosynthetic organism such as an alkaliphilic (high pH tolerant)and/or halophilic alga and/or cyanobacterium, since most heterotrophs offreshwater origin cannot grow in such a brine medium with high salinity.Therefore, use of brine liquid as a high-salinity culture medium toallow only certain specially developed (or selected) salt-tolerantphotosynthetic organisms such as certain highly salinity-tolerant rarealgae (or cyanobacteria) strains to grow can represent a significantmethod to helping overcome this technical challenge in mass culture.That is, application of the photovoltaic panel-interfaced distillationsolar-greenhouse system and its associated brine product as a tool todevelop, screen, and culture certain special/rare salt-tolerantphotosynthetic organisms is also an important strategy to enableutilization of brine liquid to grow a specially developed (or selected)salt-tolerant alga and, at the same time, to minimize undesirableheterotrophs in algal mass culture for photobiological production ofadvanced biofuels and bioproducts.

According to one of the various embodiments, algal salinity toleranceand other stress (including but not limited to pH, heat, and/or cold)tolerance can be measured by measuring their rates of photosynthesissuch as CO₂ fixation and/or O₂ evolution in the presence of highsalinity and/or alkaline pH in the liquid culture medium at varioustemperature conditions. Use of a dual- and/or multi-reactor-flowdetection system can facilitate the measurements that includesimultaneous measurement of CO₂ fixation, pH, O₂ and H₂ evolution, cellsdensity, and actinic intensity. The advantage of a dual-(ormulti)-reactor-flow detection system is that it allows to assay two ormultiple different samples simultaneously at virtually identicalconditions. Any systematic error of the dual-reactor system can beeliminated by interchanging two samples between the two reactors foreach replication of assays. Therefore, use of this type ofdual-reactor-flow systems can provide reliable measurements forscreening of salinity tolerance and/or other environmental stresstolerance. The tolerance of other environmental stresses (such asalkalinity, heat and cold stresses) can be similarly measured andscreened.

In one of the preferred embodiments, photosynthetic organisms fordevelopment and screening for high salinity tolerance are selected fromthe group consisting of algae and/or blue-green algae. The use of algaeand/or blue-green algae has several advantages. They can be grown in anopen pond and/or a photobiological reactor at large amounts and lowcosts. Algae suitable for development and screening of high salinitytolerance in accordance of the present invention include bothunicellular algae and multi-unicellular algae. Multicellular algae thatcan be selected for use in this invention include, but are not limitedto, seaweeds such as Ulva latissima (sea lettuce), Ascophyllum nodosum,Codium fragile, Fucus vesiculosus, Eucheuma denticulatum, Gracilariagracilis, Hydrodictyon reticulatum, Laminaria japonica, Undariapinntifida, Saccharina japonica, Porphyra yezoensis, and Porphyratenera. Suitable algae can also be chosen from the following divisionsof algae: green algae (Chlorophyta), red algae (Rhodophyta), brown algae(Phaeophyta), diatoms (Bacillariophyta), and blue-green algae(Oxyphotobacteria including Cyanophyta and Prochlorophytes). Suitableorders of green algae include Ulvales, Ulotrichales, Volvocales,Chlorellales, Schizogoniales, Oedogoniales, Zygnematales, Cladophorales,Siphonales, and Dasycladales. Suitable genera of Rhodophyta arePorphyra, Chondrus, Cyanidioschyzon, Porphyridium, Gracilaria,Kappaphycus, Gelidium and Agardhiella. Suitable genera of Phaeophyta areLaminaria, Undaria, Macrocystis, Sargassum and Dictyosiphon. Suitablegenera of Cyanophyta (also known as Cyanobacteria) include (but notlimited to) Phoridium, Synechocystis, Syncechococcus, Oscillatoria, andAnabaena. Suitable genera of Prochlorophytes (also known asoxychlorobacteria) include (but not limited to) Prochloron,Prochlorothrix, and Prochlorococcus. Suitable genera of Bacillariophytaare Cyclotella, Cylindrotheca, Navicula, Thalassiosira, andPhaeodactylum.

Preferred species of algae for use in the present invention include (butnot limited to): Dunaliella salina, Dunaliella viridis, Dunaliellabardowil, Crypthecodinium cohnii, Schizochytrium sp., Chlamydomonasreinhardtii, Platymonas subcordiformis, Chlorella fusca, Chlorellasorokiniana, Chlorella vulgaris, ‘Chlorella’ ellipsoidea, Chlorellaspp., Haematococcus pluvialis; Parachlorella kessleri, Betaphycusgelatinum, Chondrus crispus, Cyanidioschyzon merolae, Cyanidiumcaldarium, Galdieria sulphuraria, Gelidiella acerosa, Gracilariachangii, Kappaphycus alvarezii, Porphyra miniata, Ostreococcus tauri,Porphyra yezoensis, Porphyridium sp., Palmaria palmata, Gracilaria spp.,Isochrysis galbana, Kappaphycus spp., Laminaria japonica, Laminariaspp., Monostroma spp., Nannochloropsis oculata, Porphyra spp.,Porphyridium spp., Undaria pinnatifida, Ulva lactuca, Ulva spp., Undariaspp., Phaeodactylum Tricornutum, Navicula saprophila, Cylindrothecafusiformis, Cyclotella cryptica, Euglena gracilis, Amphidinium sp.,Symbiodinium microadriaticum, Macrocystis pyrifera, Ankistrodesmusbraunii, Scenedesmus obliquus, Stichococcus sp., Platymonas sp.,Dunalielki sauna, and Stephanoptera gracilis.

Preferred species of blue-green algae (oxyphotobacteria includingcyanobacteria and oxychlorobacteria) for development and screening ofhigh salinity tolerance in accordance of the present invention include(but not limited to): Thermosynechococcus elongatus BP-1, Nostoc sp. PCC7120, Synechococcus elongatus PCC 6301, Syncechococcus sp. strain PCC7942, Syncechococcus sp. strain PCC 7002, Syncechocystis sp. strain PCC6803, Prochlorococcus marinus MED4, Prochlorococcus marinus MIT 9313,Prochlorococcus marinus NATL1A, Prochlorococcus SS120, Spirulinaplatensis (Arthrospira platensis), Spirulina pacifica, Lyngbyamajuscule, Anabaena sp., Synechocystis sp., Synechococcus elongates,Synechococcus (MC-A), Trichodesmium sp., Richelia intracellularis,Synechococcus WH7803, Synechococcus WH8102, Nostoc punctiforme,Syncechococcus sp. strain PCC 7943, Synechocyitis PCC 6714phycocyanin-deficient mutant PD-1, Cyanothece strain 51142, Cyanothecesp. CCY0110, Oscillatoria limosa, Lyngbya majuscula, Symploca muscorum,Gloeobacter violaceus, Prochloron didemni, Prochlorothrix hollandica,Prochlorococcus marinus, Prochlorococcus SS120, Synechococcus WH8102,Lyngbya majuscula, Symploca muscorum, Synechococcus bigranulatus,cryophilic Oscillatoria sp., Phormidium sp., Nostoc sp.-1, Calothrixparietina, thermophilic Synechococcus bigranulatus, Synechococcuslividus, thermophilic Mastigocladus laminosus, Chlorogloeopsis fritschiiPCC 6912, Synechococcus vulcanus, Synechococcus sp. strain MA4,Synechococcus sp. strain MA19, and Thermosynechococcus elongatus.

According to another embodiment, a salinity-tolerant photosyntheticorganism can be developed through a mutagenesis/molecular geneticengineering and screening process that comprises the following steps: a)Mutagenizing and/or molecular genetic engineering of photosyntheticorganisms; b) Selecting high salinity tolerant photosynthetic organismsin the presence of saline/brine at a critical salt concentration; c)Growing selected photosynthetic organisms into colonies for isolationand further selection; d) Growing a selected colony into a brine liquidculture; e) Further screening for high salt-tolerant photosyntheticorganisms by measuring photosynthesis rate in the presence of highsalinity at a salt concentration range from 3% to about 36% (saltsaturation) and/or under certain other environmental conditionsincluding (but not limited to) alkalinity, heat and cold stresses; andf) repeating steps a) through e) for a plurality of operational cyclesto achieve more desirable results.

In practice, any of the steps a) through f) of this salt-tolerancedeveloping process are applied in full or in part, and/or in anyadjusted combination to achieve more desirable results. In one of thevarious embodiments, for example, the step of mutagenizingphotosynthetic organisms is carried out by a series of mutagenesistechniques such as radiation induced mutagenesis, insertionalmutagenesis, chemical-induced mutagenesis, and molecular geneticengineering of ion channels and ion transporters in cellar and subcellar(organelles) membranes that are known to those skilled in the art.

Development and screening for high-salinity tolerant photosyntheticorganisms in combination with proper selection for their geneticbackgrounds and certain special features is also beneficial. Forexample, a highly salt-tolerant designer alga created from cryophilicalgae (psychrophiles) that can grow in snow and ice, and/or fromcold-tolerant host strains such as Chlamydomonas cold strain CCMG1619,which has been characterized as capable of performing photosyntheticwater splitting as cold as 4° C. (Lee, Blankinship and Greenbaum (1995),“Temperature effect on production of hydrogen and oxygen byChlamydomonas cold strain CCMP1619 and wild type 137c,” AppliedBiochemistry and Biotechnology 51/52:379-386), permits photobiologicalmass culture with saline/brine liquid media even in cold seasons orregions such as Canada. Meanwhile, a highly salinity-tolerant designeralga created from a thermophilic/thermotolerant photosynthetic organismsuch as thermophilic algae Cyanidium caldarium and Galdieria sulphurariaand/or thermophilic cyanobacteria (blue-green algae) such asThermosynechococcus elongatus BP-1 and Synechococcus bigranulatus maypermit the practice of this invention to be well extended into the hotseasons or areas such as Mexico and the Southwestern region of theUnited States including Nevada, California, Arizona, New Mexico andTexas, where the weather can often be hot. Additional optional featuresof a highly salinity-tolerant designer alga include the benefits ofreduced chlorophyll-antenna size, which has been demonstrated to providehigher photosynthetic productivity (Lee, Mets, and Greenbaum (2002).“Improvement of photosynthetic efficiency at high light intensitythrough reduction of chlorophyll antenna size,” Applied Biochemistry andBiotechnology, 98-100: 37-48). By use of a phycocyanin-deficient mutantof Synechocystis PCC 6714, it has been experimentally demonstrated thatphotoinhibition can be reduced also by reducing the content oflight-harvesting pigments (Nakajima, Tsuzuki, and Ueda (1999) “Reducedphotoinhibition of a phycocyanin-deficient mutant of Synechocystis PCC6714”, Journal of Applied Phycology 10: 447-452). Therefore, in one ofthe various embodiments, a highly salinity-tolerant alga is selectedfrom the group consisting of green algae, red algae, brown algae,blue-green algae (oxyphotobacteria including cyanobacteria andprochlorophytes), diatoms, marine algae, freshwater algae, unicellularalgae, multicellular algae, seaweeds, alkaliphilic algal strains,halophilic algal strains, cold-tolerant algal strains, heat-tolerantalgal strains, light-harvesting-antenna-pigment-deficient mutants, andcombinations thereof.

According to another embodiment, a photovoltaic panel-interfaceddistillation solar-greenhouse system (FIG. 4) can also be used to screenin-situ for salinity-tolerant photosynthetic organisms. For example, asthe solarhouse distillation operates, when the salinity of thedistillation liquid reaches a desired critical level, an inoculum sample(a relatively small volume, e.g., for about 0.1 to 1 liter) of algae orcyanobacteria culture (preferably at their logarithmic growth phasetypically with their chlorophyll (Chl) concentration in a range of about0.5-3 micrograms Chl per ml of liquid culture) can beintroduced/inoculated into the distillation chamber saline/brine liquid(volumes 10 to 1000 liters, for example). Although this amount ofinocular sample typically contains more than hundreds millions of algalcells, its introduction into a relatively large distillation chamberliquid (10 to 1000 liters, for example) does not significantly affectthe optical properties of the distillation chamber liquid so that itwill have no significant impact on the performance of the photovoltaicpanel electricity generation. In this case, to provide aphotoautotrophic growth condition as needed, the distillationsaline/brine liquid is optionally supplemented with certain inorganicnutrients such as N, P, K at 1-10 mM concentration range. Photosyntheticculture growth may also require other mineral nutrients such as Mg, Ca,S, and Cl at the concentrations of about 0.5 to 1.0 mM, plus some traceelements Mn, Fe, Cu, Zn, B, Co, Mo among others at μM concentrationlevels. Depending on the brine sources, however, brine liquid typicallycontains sufficient amounts of these mineral nutrients. When/if needed,however, all of the mineral nutrients can be supplied in an aqueousminimal medium that can be made with well-established recipes of algalculture media using relatively small of inexpensive fertilizers andmineral salts such as ammonium bicarbonate (NH₄HCO₃) (or ammoniumnitrate, urea, ammonium chloride), potassium phosphates (K₂HPO₄ andKH₂PO₄), magnesium sulfate heptahydrate (MgSO₄.7H₂O), calcium chloride(CaCl₂), zinc sulfate heptahydrate (ZnSO₄.7H₂O), iron (II) sulfateheptahydrate (FeSO₄.7H₂O), and boric acid (H₃BO₃), among others.

Among the inoculated algal (microbial) cells, only those that cantolerate high salinity and have the ability to perform photoautotrophicgrowth will be able to grow in the solarhouse distillation saline/brineliquid with the supply (feeding) of CO₂ (FIG. 4). Other algal cells thatthat cannot tolerate the high salinity will likely be photobleached bythe sunlight and then die off typically within a few weeks, depending onthe geographic location and weather conditions. It could take about 3months or more (depending on growth conditions) for a single algal cellof high-salinity tolerance to populate the distillation chambersaline/brine liquid (volumes 10 to 1000 liters in this example) to acommonly visible level (about 0.5 microgram of Chl per ml). Because ofthe logarithmic feature of cells population growth pattern, for themajority (about 90%) of the time (e.g., 90 days), the distillationchamber saline/brine liquid (volumes 10 to 1000 liters in this example)stays essentially colorless, which is perfect to allow sunlight to gothrough for solar electricity generation by the photovoltaic panelsunderneath the distillation chamber saline/brine liquid. This featurealso makes it quite attractive to use a solar-panel-interfaceddistillation solarhouse for simultaneous production of electricity,freshwater, and, at the same time, for developing and screening in-situfor highly salinity-tolerant photosynthetic organisms while generatingsolar electricity. The salinity of the distillation liquid can beadjusted to any desired levels by adjusting the addition of newdistillation liquid in relation to the solarhouse distillation liquidevaporation rate. Therefore, use of a solarhouse distillation systemsuch as that shown in FIG. 4 can achieve in situ screening forsalinity-tolerant photosynthetic organisms with a series of saltconcentrations (salinity) levels from about 3% salt to: 4%, 5%, 6%, 7%,8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%,23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, up to the salt saturationconcentration of about 35-36% salt in brine liquid.

When a high-salinity tolerant algal culture is obtained through theapplication of the solarhouse photobiological screening/culturingprocess (FIG. 4), the algal cell culture can then be characterized formany applications with arts known to those in the field. For example,use of high-salinity tolerant photosynthetic organisms as host organismswith synthetic biology/genetic transformation can create a series ofhigh-salinity tolerant designer photosynthetic organisms for productionof advanced biofuels such as hydrogen (H2), ethanol, butanol, pentanol,methanol biooils, biodiesel and etc. The arts for creating designerphotosynthetic organisms through molecular genetics in combination withsynthetic biology have recently been disclosed in InternationalApplication No. PCT/US2009/034780 and elsewhere.

According to one of the various embodiments, to achieve desirableresults, a highly salinity tolerant photosynthetic organism such as algaor blue-green alga should be able to tolerate salinity at least above 5%salt, preferably above 10% salt, more preferably above 15% salt, andmost preferably above 20% up to salt saturation concentration (about 35%salt) in a brine liquid culture medium. Success of developing such asuper-high salinity tolerant strain of algae or blue-green algae (i.e.,oxyphotobacteria such as cyanobacteria) that can tolerate above 20% upto saturation salt concentration (about 35% salt) in liquid culturemedia will enable productive utilization of brine liquid as aphotobiological mass culture medium. Since most of the heterotrophicmicroorganisms of freshwater and/or seawater (3% salt) origin wouldunlikely be able to tolerate such a high salinity (20-35% salt), use ofa super-high salinity tolerant (rare) algal strain that can use such ahigh-salt brine liquid (containing about 20-35% salt) will make it mucheasier to grow/maintain a relatively pure mass algal culture in brineliquid for photobiological production of advanced biofuels andbioproducts from CO₂ and H₂O. The advanced biofuels and bioproducts thatmay be produced through brine photobiological (algal) mass culture withsynthetic biology applications are selected from the group consistingof: hydrogen (H2), ethanol, butanol/isobutanol, propanol, pentanol,hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol,tetradecanol, cetyl alcohol, stearyl alcohol, long chain alcohols,branched chain alcohols, higher alcohols, isoprenoids, hydrocarbons,biooils, methanol, biodiesel, lipids, DHA (docosahexaenoic acid) omega-3fatty acid, EPA (eicosapentaenoic acid) omega-3 fatty acid, ARA(arachidonic acid) omega-6 fatty acid, acetic acid, proteins,chlorophylls, carotenoids, phycocyanins, allophycocyanin, phycoerythrin,their derivatives/related product species, and combinations thereof.

Note, when seawater (containing about 3% salt) is solarhouse-distilledto the level of high-salt brine liquid (containing about 20-35% salt) inaccordance of the present invention, nearly 90% of its water isextracted as freshwater. The residual brine liquid (containing about20-35% salt) can now be used as a mass culture medium to grow thespecially developed super-high salinity tolerant (rare) algae (oroxyphotobacteria) for photobiological production of advanced biofuelsand bioproducts. The used brine algal culture can be harvested forextraction of biomass and biofuels (such as lipids/biooils), orprocessed through further distillation/evaporation to make a dry algalbiomass/salt mixture that may be used as animal feed supplement. Inaddition, the dry algal biomass/salt mixture can also be pyrolyzed orcombusted to produce energy and crude salt that could have otherapplications including for use as a deicing road salt. Therefore, thisembodiment also represents a holistic clean solarphotovoltaic/distillation energy technology system that can produceelectricity, freshwater, sea salt, and brine algal culture with nearlyzero waste discharge.

Operations of Multiple Distillation Solarhouses

According to one embodiment, any number of various distillationphotovoltaic panel-interfaced distillation solarhouses (such as 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, and etc.) may be used in series, inparallel, and/or in combination with photobioreactor greenhousedistillation systems to achieve more desirable results including (butnot limited to) production and harvesting of advanced biofuels andbioproducts such as ethanol. Examples of these embodiments areillustrated in FIGS. 9A and 9B with an integrated system 900 ofphotovoltaic panel-interfaced distillation solarhouses coupled withethanol-producing brine photobiological culture distillation greenhousefor ethanol production and harvesting with multistage distillation whilegenerating solar electricity. As mentioned before, InternationalApplication No. PCT/US2009/034780 has recently disclosed certain methodson synthetic biology to create designer photosynthetic organisms (suchas blue-green algae) for photobiological production of advanced biofuelssuch as ethanol from carbon dioxide CO₂ and water H₂O, and on agreenhouse distillation system technology to harvest thephotobiologically produced ethanol from the ethanol-producing algalliquid mass culture. The exemplary embodiment of FIG. 9A illustrates howthe condensate collected by the ducts in a photobiologicalethanol-producing reactor 950/greenhouse can be transferred with acondensate-transporting tube 908 into the next solarhouse forre-distillation using a combined system 900 of multiple photovoltaicpanel-interfaced solar-greenhouses. According to one of the variousembodiments, it is a preferred practice to place the condensatecollecting ducts in the first distillation greenhouse high enough sothat the condensate collected by the ducts there can flow through acondensate-transporting tube into the next distillation solarhouse byuse of gravity without requiring any pumping. As shown in FIG. 9A, theoutlet of the condensate-transporting tube 908 should be immersed in theliquid, for example, beer 904 of the next solarhouse so that anyundesirable exchange of vapor between the greenhouse and the solarhouseis properly blocked by the liquid.

The second solarhouse shown in FIG. 9A (middle) is an example of a solarpanel-interfaced distillation chamber system where a liquid beer 904from the photobiological ethanol-producing reactor 950/greenhouse isre-distilled using the solar waste heat from the photovoltaic panel 101beneath the distillation chamber. That is, the condensate from thegreenhouse (on the left, FIG. 9A) is transported through a tube into thesolarhouse distillation chamber (middle, FIG. 9A) for redistillation.The distillation chamber and the photovoltaic panel of the solarhouse(middle, FIG. 9A) are separated by a transparent and impermeable plateand/or film (or membrane) 903 that allows only sunlight and heat to gothrough. Use of sunlight drives photovoltaic cells and co-generates heatenergy that can raise the temperature of the distillation chamber abovethe photovoltaic panel. The co-generated solar heat is then used forre-evaporation of the ethanol-containing liquid (beer) at thedistillation chamber above the photovoltaic panel 101. The vapor 913 isthen re-condensed onto the inner surface of the ceiling 905 in thesolarhouse as well. The condensate 914 of the distillation solarhouse iscollected in a similar manner by using a tilted ceiling surface and asystem of condensate-collecting ducts 907 around the greenhouse wallsbelow the ceiling. The ethanol concentration in the condensate collectedfrom the distillation greenhouse (FIG. 9A, middle) is now higher(typically in a range about 1-70% ethanol depending on the source beerand operating conditions) than that (about 0.5-40% ethanol) in thecondensate collected at the distillation greenhouse (FIG. 9A, left).Higher and higher ethanol concentration can be achieved with furtherre-distillations using the third (FIG. 9A, right) and/or moredistillation solarhouses. Therefore, this is also an example wheresunlight energy (both the photovoltaic active photons and the associatedwaste solar heat) can be effectively used simultaneously for bothphotovoltaic electricity generation 112 and liquid distillation forharvesting of ethanol 909. As the number of redistillations increase,the resulting ethanol concentration in the condensates (distillates)usually increases. The maximum achievable ethanol concentration throughthis type of fractional greenhouse distillation is 96% ethanol, which issufficiently high in quality that can be used directly as a fuel to runethanol-powered and/or flexible-fuel vehicles. Therefore, this processtechnology is designed to maximally utilize solar (both its visible andinfra-red radiation) energy for: (1) photovoltaic electricitygeneration, (2) photobiological production of ethanol from CO₂ and H₂O,for example, using CO₂ sources 919 and (3) harvesting of the productethanol through a series of distillation greenhouses and solarhouseswith higher energy efficiency and minimal cost.

Therefore, according to one of the various embodiments, the method of anethanol harvesting process with photovoltaic panel-interfaceddistillation systems comprises the following steps:

-   -   a) The designer-organism culture selected from the group        consisting of cyanobacteria and algae in a        distillation-greenhouse photobioreactor photobiologically        produces ethanol from carbon dioxide and water;    -   b) The product ethanol is harvested from the photobiological        culture by the solar-heat-driven distillation;    -   c) The condensate collected from this distillation greenhouse is        transported to the next photovoltaic-panel-based distillation        solarhouse;    -   d) Use of sunlight drives photovoltaic cells and co-generates        heat energy to raise the temperature of the distillation chamber        above the photovoltaic panel;    -   e) The co-generated solar heat is used to vaporize the        ethanol-containing liquid (beer) at the distillation chamber        above the photovoltaic panel;    -   f) The vapor is re-condensed onto the inner surface of the        ceiling in the solarhouse;    -   g) The condensate of the distillation solarhouse is collected by        using a tilted ceiling surface and a system of        condensate-collecting ducts around the greenhouse walls below        the ceiling;    -   h) The ethanol concentration in the condensate collected from        the distillation greenhouse is now higher than that in the        condensate collected at the previous distillation greenhouse;    -   i) Higher and higher ethanol concentration can be achieved with        further re-distillations using the third and/or more        distillation solarhouses operated in series, in parallel, and in        combination thereof.

According to one of the various embodiments, the method of an ethanolharvesting process with photovoltaic panel-interfaced distillationsystems comprises also the steps of using hydrophobic microporousmembrane distillation systems (FIGS. 2F, 2G, 8F and 8G). For example, byfeeding a source liquid beer into the liquid feed chamber 8804 of amembrane distillation system 8800 as shown in FIG. 8G, a higher ethanolconcentration (higher than that of the source liquid beer) is achievedin the condensate liquid 8876 through both direct contact membranedistillation and/or air gap membrane distillation. Higher and higherethanol concentration can be achieved with further re-distillationsusing a second, third, and/or more membrane distillation systems (FIGS.2F, 2G, 8F and 8G) operated in series, in parallel, and in combinations.

Note, sometimes, the product ethanol concentration in a large volume ofthe photobiological liquid culture medium could be as low as below 0.1%ethanol. It would be impractical to use the conventionalethanol-separation technologies such as theboiler-distillation-column-based ethanol-separation technologies toharvest ethanol from such a low concentration in such a large volume ofthe liquid live culture medium. However, with use of the solarhousedistillation technology (FIGS. 1-9), it is possible to harvest and/orenrich from such a dilute ethanol concentration (which sometimes couldbe as low as below 0.1% ethanol) of a photobiological liquid culturemedium to first produce a beer liquid (condensate) that contains morethan 3% ethanol so that can then be further processed with certainconventional ethanol-separation technologies including theboiler-distillation-column-based ethanol-separation technologies. Inthis case, the greenhouse distillation and photovoltaic panel-interfacedsolarhouse distillation technology (FIGS. 1-9) can also be used incombination with the conventional ethanol-separation technologiesincluding the boiler-distillation-column-based ethanol-separationtechnologies. In addition to solar electricity generation andphotobiological production and harvesting of product ethanol, use of thetechnology can also produce freshwater, saline/brine products, and usedbrine biomass culture as byproducts. Therefore, the present invention isexpected to have multiple applications with a higher solar-to-productsenergy-conversion efficiency than the current technology.

FIG. 9B also represents an example of an integrated solar photovoltaicelectricity generation, photobiological ethanol-production andsolar-heat-driven distillation system 900 which comprises multipledistillation solarhouses in combination with distillation greenhouse(s).In this example, the designer-organism culture 954, which is maintainedin the first distillation-greenhouse photobioreactor 950 (FIG. 9B,upper) using a brine culture inlet 951 and an adjustable brine cultureoutlet 952, photobiologically produces ethanol from carbon dioxide CO₂and water H₂O, using CO₂ sources 919. The product ethanol is harvestedfrom the photobiological culture 954 by the solar-heat-drivendistillation. The condensate collected from this distillation greenhouse(FIG. 9B, upper) is transported to the next photovoltaic-panel-baseddistillation solarhouse (FIG. 9B, middle) where the condensate isre-distillated with a series of distillation compartments. According toone of various embodiments, any number of distillation compartments(such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and etc.) can be used inseries and/or in parallel. As mentioned before, when the beer liquidpasses through the distillation compartments (or distillationsolarhouses) in series, the ethanol content in the beer liquid can beremoved so that the residual liquid exiting from the lastre-distillation compartment (distillation greenhouse or solarhouse)becomes largely pure freshwater that may be recycled for making culturemedia and/or for other use. That is, use of this integrated photovoltaicand brine photobiological ethanol-production process technology can alsoproduce freshwater as a byproduct.

The condensates from the re-distillation are transferred to the thirdsolarhouse (FIG. 9B, bottom), which can also comprises multipledistillation compartments for re-distillation. The final distillatesfrom the third distillation solarhouse typically contain 10-90% ethanol,largely depending on the ethanol content of the source beers. Higherethanol concentration can be achieved with further re-distillation.According to one of the various embodiments, any number of distillationcompartments and/or solarhouses (such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,12, and etc.) can be used in series and/or in parallel. As the number ofre-distillations increase, the resulting ethanol concentration in thecondensates increases. The maximum achievable ethanol concentrationthrough this type of fractional distillation is 96% ethanol with 4%water, because, at this concentration (96% ethanol, which is also knownas an azeotropic mixture), the ethanol in the vapor is no longer moreconcentrated than that in the liquid phase and consequently thefractional distillation reaches its limit.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications willreadily appear to those skilled in the art. For instance, thephotovoltaic panel-interfaced distillation solarhouse technology systems(FIGS. 1-9) have been disclosed here in considerable detail withexamples of producing freshwater and sea salt, and harvesting organicsolvent/biofuel ethanol from a brine algal culture while generatingphotovoltaic electricity with utilization of solar waste heat. The sameprinciple and methodologies disclosed here can be applied for othersimilar distillation liquids in addition to seawater as listed above:brackish water, saline water, brine liquid, surface water, groundwater,well-water, photobiological liquid culture media, beer, methanolsolutions, ethanol solutions, propanol solutions, 1-hydroxy-2-propanonesolutions, butanol solutions, cyclohexanol solutions, tert-amyl alcohol,pentanol solutions, hexadecan-1-ol solutions, polyhydric alcoholssolutions, alicyclic alcohols solutions, primary alcohol solutions,higher alcohols solutions, aldehyde solutions, aldehyde hydratesolutions, carboxylic acids solutions, lactose solutions,biomass-derived hydrolysate solutions, glucose solutions, fructosesolutions, sucrose solutions, furanose solutions, pyranose solutions,monosaccharides solutions, oligosaccharides solutions, polysaccharidessolutions, acetic acid solutions, propionic acid solutions, citric acidsolutions, lactic acid solutions, acetone solutions, and other organicsolutions and/or solvents, and combinations thereof.

Therefore, the invention in its broader aspects is not limited to thespecific details, representative apparatus and methods, and illustrativeexamples shown and described. Accordingly, departures may be made fromsuch details without departing from the spirit or scope of applicant'sgeneral inventive concept.

What is claimed is:
 1. A method for photovoltaic panel-interfacedliquid-evaporation-vapor-condensation distillation with and without ahydrophobic microporous plate membrane distillation process, the methodcomprising: creating a photovoltaic panel-interfaced distillation systemcomprising a photovoltaic panel and a distillation feed liquid inthermal contact with the photovoltaic panel; and operating thephotovoltaic panel-interfaced distillation to generate distillationproducts by using solar waste heat associated with electricitygeneration by the photovoltaic panel to drive both electricitygeneration and liquid distillation with and without a hydrophobicmicroporous membrane distillation process to make the distillationproducts from the distillation feed liquid wherein the distillation feedliquid is selected from the group consisting of seawater, brackishwater, saline water, brine liquid, surface water, ground water,well-water, non-potable water, photobiological liquid culture media, andbeer and the distillation products are selected from the groupconsisting of freshwater, distilled water, distilled ethanol, hot steam,salt, saline, brine, biofuels, and bioproducts.
 2. The method accordingto claim 1, wherein creating the photovoltaic panel-interfaceddistillation system comprises creating an air-erectable and floatablephotovoltaic panel-interfaced solarhouse distillation system withcondensate collecting ducts.
 3. The method according to claim 1, whereincreating the photovoltaic panel-interfaced distillation system comprisescreating an air-erectable and floatable photovoltaic panel-interfacedsolarhouse distillation system with automatic liquid feed intake andrelease.
 4. The method according to claim 3, wherein operating theair-erectable and floatable photovoltaic panel-interfaced solarhousedistillation system comprises: placing the solarhouse distillationsystem in seawater; and adjusting buoyancy of the solarhousedistillation system so that a surrounding seawater level is higher thana distillation feed liquid level in a distillation chamber of thesolarhouse distillation system to enable automatic intake and release ofthe distillation feed liquid; through at least one source liquid inletvalve in communication with the seawater and the distillation chamberand located under the surrounding seawater level.
 5. The methodaccording to claim 1, wherein: creating the photovoltaicpanel-interfaced distillation system comprises creating an erectablearch-shaped distillation liquid chamber system comprising a layer ofhydrophilic transparent material wettable with distillation liquid; andthe hydrophilic transparent material is selected from the groupconsisting of hydrophilic transparent polymer materials, hydrophilicacrylate, methacrylate polymer, super-hydrophilic and transparent thinfilms of TiO₂ nanotube arrays, transparent hydrophilic TiO₂ thin film,hydrophilic sol-gel derived SiO₂/TiO₂ transparent thin film, polyalcoholdiepoxide, polyvinylpyrrolidone and polydimethacrylamide-copolymers withpolymerizable α unsaturated groups plus polyisocyanates and anionicsurfactants, hydrophilic polyacrylic acid network-structured materials,hydrophilic transparent resin, transparent hydrophilic paint,hydrophilic glass fibers, hydrophilic glass beads, hydrophilictransparent gel materials, hydrophilic organic transparent gel,hydrophilic cellulose thin transparent film, hydrophilic transparentplastic fibers, porous poly(methyl methacrylate) films, Ti-containingmesoporous silica thin films, porous transparent hydrophilic plasticfilms, and combinations thereof.
 6. The method according to claim 1,wherein creating the photovoltaic panel-interfaced distillation systemcomprises creating an air-erectable and floatable photovoltaicpanel-interfaced hydrophobic porous plate membrane distillation systemfor use in seawater and on land, the air-erectable and floatablephotovoltaic panel-interfaced hydrophobic porous plate membranedistillation system comprising: electricity output terminals incommunication with the photovoltaic panel and a heat-conducting filmcovering a back surface of the photovoltaic panel; 2) a liquid feedchamber comprising a heat-conducting film top and a hydrophobicmicroporous plate bottom; 3) a source liquid inlet and a liquid outletin communication with the liquid feed chamber; 4) a base condensationchamber containing air space and condensate liquid space; and 5)solarhouse walls extending between with the heat-conducting film and thehydrophobic microporous plate to form the liquid feed chamber and thebase condensation chamber.
 7. The method according to claim 6, wherein:said hydrophobic microporous plate comprises a hydrophobic microporousmembrane constructed on a porous plate support material; the hydrophobicmembrane is made from hydrophobic polymer materials that are selectedfrom the group consisting of polypropylene (PP), polytetrafluoroethylene(PTFE), polyvinylidene fluoride (PVDF), polyethelene (PE), andcombinations thereof; and the support plate material is selected fromthe group consisting of porous carbon fiber plates, porous glass fiberplates, porous plastic plates, fiberglass-reinforced plastic materials,carbon fiber composite materials, vinyl ester, epoxy materials, porouspolytetrafluoroethylene plates, porous glass plates, porous aluminumplates, porous stainless steel plates, and combinations thereof.
 8. Themethod according to claim 6, wherein said photovoltaic panel-interfacedhydrophobic microporous plate membrane distillation system comprises: a)hydrophobic membrane pore sizes selected from the group consisting of 8micrometers (μm), 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1.5 μm, 1.0 μm, 0.8 μm,0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.05 μm, 0.02 μm, 0.01μm, 0.005 μm, and within a range bounded by any two of these values; b)a hydrophobic membrane thickness is-selected from the group consistingof 10 millimeters (mm), 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.8 mm, 0.6 mm,0.4 mm. 0.2 mm, 0.1 mm, 0.05 mm, 0.02 mm, and within a range bounded byany two of these values; c) salt rejection in hydrophobic microporousplate distillation preferably over 99%, more preferably over 99.9%, and,most preferably, over 99.99%; d) hydrophobic microporous plate membranedistillation productivity at a level selected from the group consistingof more than 0.5 liter of product water per square meters of membraneper day (L/m² day), 1 L/m² day, 2 L/m² day, 4 L/m² day, 6 L/m² day, 8L/m² day, 10 L/m² day, 12 L/m² day, 14 L/m² day, 18 L/m² day, 20 L/m²day, 30 L/m² day, 60 L/m² day, 120 L/m² day, and within a range boundedby any two of these values; e) hydrophobic microporous platedistillation energy efficiency at a level selected from the groupconsisting of 30%, 40%, 50%, 60%, 70%, 80%, and within a range boundedby any two of these values; and f) a temperature difference between thehot feed liquid and the cooled condensate liquid at a value selectedfrom the group consisting of 0.1° C., 0.2° C., 0.5° C., 1° C., 2° C., 3°C., 4° C., 5° C., 6° C., 8° C., 10° C., 15, 20° C., 25° C., 30° C., 35°C., 40° C., 45° C., 50° C., 60° C., 70° C., 80° C., and within a rangebounded by any two of these values.
 9. The method according to claim 1,wherein creating the photovoltaic panel-interfaced distillation systemcomprises creating an air-erectable and floatable photovoltaicpanel-interfaced hydrophobic porous plate membrane distillation systemfor use on water including seawater surface, which comprises:electricity output terminals in communication with the photovoltaicpanel and a heat-conducting film covering a back surface of thephotovoltaic panel; a liquid feed chamber comprising a heat-conductingfilm top and a hydrophobic microporous plate membrane bottom; at leastone pair of energy-saving liquid feed and/discharge tubes incommunication with the liquid feed chamber; a base condensation chambercomprising contains air space and condensate liquid space, thehydrophobic microporous plate comprising a base condensation chambertop; solarhouse walls extending between and joining the heat-conductingfilm and hydrophobic microporous plate; and a condensate outlet incommunication with a base condensation chamber bottom for harvestingdistillation products.
 10. The method according to claim 9, whereinoperating the photovoltaic panel-interfaced hydrophobic porous platemembrane distillation system comprises: using waste heat from thephotovoltaic panel to increase vapor pressure of the distillation feedliquid in the liquid feed chamber, generating a difference in partialpressure between opposing sides of the hydrophobic microporous platemembrane; evaporating heated water in the feed chamber through nonwettedpores of the hydrophobic microporous plate membrane; condensing theheated water to form condensate droplets on a base condensation chamberinner wall surface; and collecting the condensate droplets product waterthrough a condensate outlet connected to a bottom of the basecondensation chamber.
 11. The method according to claim 1, whereincreating photovoltaic panel-interfaced distillation system comprisescreating a coolant-coupled photovoltaic solar-greenhouse distillationsystem comprising: a coolant circulating photovoltaic solarhouse systemthat generates hot coolant while co-generating electricity; and acoolant-coupled distillation chamber system that generates distillationproducts by using the heat through heat-exchange with the hot coolant.12. The method according to claim 11, wherein operating the photovoltaicpanel-interfaced distillation system comprises: circulating coolant flowto cool the photovoltaic panel during solar electricity generation; andutilizing waste heat from the circulating coolant flow to makefreshwater through distillation of distillation feed liquid.
 13. Themethod according to claim 1, wherein creating photovoltaicpanel-interfaced distillation system comprises creating acoolant-coupled photovoltaic panel-interfaced hydrophobic microporousplate membrane distillation system by: creating a coolant circulatingphotovoltaic solar-interfaced membrane distillation system thatgenerates hot condensate liquid while co-generating electricity by:forming a liquid feed chamber below the photovoltaic panel by placing aheat-conducting film on a back surface of the photovoltaic panel andextending heat-insulating liquid-tight and air-tight-sealing walls fromthe heat-conducting film to a hydrophobic microporous plate membranebottom; forming a condensation liquid chamber below the liquid feedchamber by extending the heat-insulating liquid-tight andair-tight-sealing walls from the hydrophobic microporous plate membraneto a heat-insulating base plate bottom; connecting a hot coolant outletand a liquid coolant circulating tube to the condensation liquidchamber; and connecting a source liquid inlet and a liquid outlet to theliquid feed chamber; and creating a coolant-coupled distillation chambersystem that generates distillation products by using the heat throughheat-exchange with the hot coolant by: forming a coolant chambercomprising an insulated base bottom and a heat-conducting plate film andconnecting the coolant chamber to the condensation liquid chamberthrough the hot liquid coolant outlet and the liquid coolant circulatingtube; forming a distillation chamber system comprising a distillationhouse ceiling top and a heat-conducting film bottom, theheating-conducting film heat exchange with the coolant chamber;connecting a condensate collecting tank to the liquid coolantcirculating tube; and connecting a seawater inlet to the distillationchamber containing distillation liquid and vapor and, a condensatecollecting tube to a freshwater collecting tank.
 14. The methodaccording to claim 13, wherein operating the photovoltaicpanel-interfaced hydrophobic porous plate membrane distillation systemcomprises: employing a membrane distillation process across thehydrophobic microporous plate in between the solar panel-interfacedliquid feed chamber and the condensation liquid chamber; heating feedsaline water by waste heat from photovoltaic panel to increase its vaporpressure, generating a difference in partial pressure at opposing sidesof the hydrophobic microporous plate membrane; evaporating hot water inthe liquid feed chamber through nonwetted pores of the hydrophobicmicroporous plate membrane; passing vapor through the hydrophobicmicroporous plate membrane and condensing the vapor directly into coolerliquid condensate of the condensation liquid chamber to producedistilled water; collecting the distilled water product from thehydrophobic microporous plate membrane distillation process thecondensate collecting tank; and keep a condensate tube outlet of thecondensate collecting tank immersed under a condensate liquid level inthe condensate collecting tank to collect the distilled water throughthe liquid coolant circulating tube without introducing air bubbles intothe liquid coolant circulating tube.
 15. The method according to claim1, wherein creating the photovoltaic panel-interfaced distillationsystem comprises creating a photovoltaic panel-interfaced hydrophobicmicroporous plate membrane distillation system by: forming a liquid feedchamber below the photovoltaic panel by placing a heat-conducting filmon a back surface of the photovoltaic panel and extendingheat-insulating liquid-tight and air-tight-sealing walls from theheat-conducting film to a hydrophobic microporous plate membrane bottom;forming a condensation liquid chamber below the liquid feed chamber byextending the heat-insulating liquid-tight and air-tight-sealing wallsfrom the hydrophobic microporous plate membrane to a heat-insulatingbase plate bottom; a top surface of the photovoltaic panel with ananti-reflection and heat-insulating transparent film covering;connecting a source liquid inlet and a liquid outlet to the liquid feedchamber; connecting a height-adjustable condensate collecting tube and aflexible outlet with the condensation chamber; and connecting acondensate outlet tube of a condensate collecting tank to theheight-adjustable condensate collecting tube.
 16. The method accordingto claim 15, wherein operating the photovoltaic panel-interfacedhydrophobic porous plate membrane distillation system comprises: usingthe height-adjustable condensate collecting tube to control a ratio ofdirect contact membrane distillation to air gap membrane distillation;placing the photovoltaic panel top surface toward a source of sunlightwith an angle above horizontal of at least 15°; controlling a condensateliquid level by adjusting a vertical distance from a upper end of thecondensation chamber to a condensate liquid level using theheight-adjustable condensate collecting tube; raising theheight-adjustable condensate collecting tube to the upper end ofcondensation chamber to establish a distance from the upper end ofcondensation chamber to the condensate liquid level of zero so that thecondensate liquid will occupy the an volume of the condensation chamberresulting in 100% direct contact membrane distillation; lowering theheight-adjustable condensate collecting tube a vertical distance equalto a vertical height of the condensation chamber so that no condensateliquid will occupy the condensation chamber resulting in 100% air gapmembrane distillation; and using the height-adjustable condensatecollecting tube to tune a ratio of direct contact membrane distillationto air gap membrane distillation to enable employment of varioushydrophobic membranes to achieve any desired ratio ofmembrane-distillation modes.
 17. The method according to claim 1,wherein creating the photovoltaic panel-interfaced distillation systemcomprises creating a sunlight-concentrating photovoltaicpanel-interfaced distillation chamber system comprising a sunlightfocusing system and a highly heat-tolerant photovoltaic panel by:placing a heat-conducting transparent protective plate between thephotovoltaic panel and the distillation feed liquid; covering thephotovoltaic panel and distillation liquid with an arch-shapedvapor-condensing transparent ceiling; walls supporting the ceiling withwalls comprising liquid-tight and air-tight-sealing materials; locatinga set of condensate-collecting ducts around the walls below a ceilinglevel; connecting a condensate collecting tube between thecondensate-collecting ducts and a condensate tank; passing a sourceliquid inlet and an adjustable liquid outlet through the walls and intocommunication with the distillation feed liquid; and passing a steamoutlet through the walls and above the distillation liquid; wherein thesunlight focusing system is position above the photovoltaic panel tofocus solar radiation on at least a portion of the photovoltaic panel.18. The method according to claim 1, wherein the photovoltaic panelcomprises a thin film solar cell panel, a cadmium telluride photovoltaicpanel, a copper indium gallium selenide solar cell panel, amultijunction photovoltaic cell panel, a dye-sensitized solar cellspanel, an organic polymer solar cells panel, a photovoltaic shingle, aphotovoltaic paint panel or combinations thereof.
 19. The methodaccording to claim 1, wherein the method further comprises: placing aheat-conducting transparent protective plate interfacing between thephotovoltaic panel and the distillation liquid in the photovoltaic panelinterfaced distillation solarhouse system; and placing a transparentvapor-condensing solarhouse ceiling over the photovoltaic panel; whereinthe transparent vapor-condensing solarhouse ceiling and theheat-conducting transparent protective plate are made from thermallyconductive transparent materials selected from the group consisting ofclear transparent plastics (Acrylic (polymethlamethacrylate), celluloseacetate butyrate, Lexan (polycarbonate), and PETG (glycol modifiedpolyethylene terphthalate), polypropylene, polyethylene, andpolyethylene HD), thermally conductive transparent plastics, transparentand thermally conductive paint, colorless glass, borosilicate glass,borosilicate glass, sol-gel, silicone rubber, quartz mineral,transparent cellulose nanofiber/epoxy resin nanocomposites,glass-ceramic materials, transparent ceramics, clear transparentplastics containing anti-reflection materials and/or coating, clearglass containing anti-reflection material coating, and combinationsthereof.
 20. The method according to claim 1, wherein the method furthercomprises using a plurality of photovoltaic panel-interfaceddistillation systems arranged in at least of series and parallel toproduce distillation products while co-generating solar electricity.